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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

X-ray fluorescence microscopy  

SciTech Connect

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

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

1990-10-01

3

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

4

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

5

X-Ray Fluorescent Recovers Ancient Text  

NSDL National Science Digital Library

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

2008-10-27

6

Coded aperture imaging for fluorescent x-rays.  

PubMed

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. PMID:24985824

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

2014-06-01

7

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

8

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

9

A miniature x-ray fluorescence setup  

NASA Astrophysics Data System (ADS)

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

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

2003-07-01

10

X-RAY FLUORESCENCE MICROPROBE (XFM) TECHNIQUES AND CAPABILITIES  

E-print Network

of materials in an "as-is" state that are chemically heterogeneous at the micrometer scale via synchrotron induced X-ray fluorescence. · XFM includes instrumentation for microbeam X-ray fluorescence (µ

Ohta, Shigemi

11

Synchrotron x-ray microbeam characteristics for x-ray fluorescence analysis  

SciTech Connect

X-ray fluorescence analysis using a synchrotron x-ray microprobe has become an indispensable technique for non-destructive micro-analysis. One of the most important parameters that characterize the x-ray microbeam system for x-ray fluorescence analysis is the beam size. For practical analysis, however, the photon flux, the energy resolution and the available energy range are also crucial. Three types of x-ray microbeam systems, including monochromatic and continuum excitation systems, were compared with reference to the sensitivity, the minimum detection limit and the applicability to various types of x-ray spectroscopic analysis. 16 refs., 5 figs.

Iida, Atsuo; Noma, Takashi [National Laboratory for High Energy Physics, Ibaraki (Japan)

1995-12-31

12

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

13

X-ray fluorescence microscopy of olfactory receptor neurons  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

14

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

15

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

16

Modern physics lab experiments using crystal X-ray generators  

SciTech Connect

Crystal X-ray generators can be made using small pyroelectric crystals such as LiTaO{sub 3} surrounded by gas at pressures of typically 15 mT. When heat is applied to one surface a strong electric field is produced at the opposite side of the crystal and electrons are accelerated toward it, giving rise to Ta L and M x-rays. On cooling the direction of the electric field reverses and a target x-ray spectrum is obtained. Two x-ray generators are described: The first is a sealed battery-powered, portable device, which can be used in routine lab experiments, such as the study of characteristic x-rays, x-ray absorption edges and x-ray fluorescence. The second is more sophisticated and is used for more advanced students. The object is to gain a better understanding of crystal x-ray generators by varying parameters such as the temperature range through which the crystal is cycled or the gas pressure or gas-type or the crystal to target distance. For both generators the decay time of the x-ray intensity can be studied as well as the x-ray spectra.

Shafroth, S. M. [Physics and Astronomy Department, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255 (United States); Brownridge, J. D. [Department of Physics, Applied Physics and Astronomy, State University of New York at Binghamton, Binghamton, New York 13901 (United States)

1999-06-10

17

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

18

The X-ray Polarimeter Experiment (XPE)  

Microsoft Academic Search

Polarimetric studies will provide a new probe of cosmic x-ray sources, supplying important clues to source geometries and emission mechanisms. However, at the present time there is only one measurement of x-ray polarization from a cosmic source, the OSO-8 detection of 19% linear polarization from the Crab Nebula. We propose a new low cost x-ray polarimeter experiment (XPE), ideally sized

R. F. Elsner; B. D. Ramsey; S. L. O'dell; M. Sulkanen; A. F. Tennant; M. C. Weisskopf; S. Gunji; T. Minamitani; R. A. Austin; J. Kolodziejczak; D. Swartz; G. Garmire; P. Meszaros; G. G. Pavlov

1997-01-01

19

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

Microsoft Academic Search

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

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

2009-01-01

20

A Monte Carlo study of x-ray fluorescence in x-ray detectors.  

PubMed

Advances in digital x-ray detector systems have led to a renewed interest in the performance of x-ray phosphors and other detector materials. Indirect flat panel x-ray detector and charged coupled device (CCD) systems require a more technologically challenging geometry, whereby the x-ray beam is incident on the front side of the scintillator, and the light produced must diffuse to the back surface of the screen to reach the photoreceptor. Direct detector systems based on selenium have also enjoyed a growing interest, both commercially and academically. Monte Carlo simulation techniques were used to study the x-ray scattering (Rayleigh and Compton) and the more prevalent x-ray fluorescence properties of seven different x-ray detector materials, Gd2O2S, CsI, Se, BaFBr, YTaO4, CaWO4, and ThO2. The redistribution of x-ray energy, back towards the x-ray source, in a forward direction through the detector, and lateral reabsorption in the detector was computed under monoenergetic conditions (1 keV to 130 keV by 1 keV intervals) with five detector thicknesses, 30, 60, 90, 120, and 150 mg/cm2 (Se was studied from 30 to 1000 mg/cm2). The radial distribution (related to the point spread function) of reabsorbed x-ray energy was also determined. Representative results are as follows: At 55 keV, more (31.3%) of the incident x-ray energy escaped from a 90 mg/cm2Gd2O2S detector than was absorbed (27.9%). Approximately 1% of the total absorbed energy was reabsorbed greater than 0.5 mm from the primary interaction, for 90 mg/cm2 CsI exposed at 100 kVp. The ratio of reabsorbed secondary (fluorescence + scatter) radiation to the primary radiation absorbed in the detectors (90 mg/cm2) (S/P) was determined as 10%, 16%, 2%, 12%, 3%, 3%, and 0.3% for a 100 kVp tungsten anode x-ray spectrum, for the Gd2O2S, CsI, Se, BaFBr, YTaO4, CaWO4, and ThO2 detectors, respectively. The results indicate significant x-ray fluorescent escape and reabsorption in common x-ray detectors. These findings suggest that x-ray fluorescent radiation redistribution should be considered in the design of digital x-ray imaging systems. PMID:10436891

Boone, J M; Seibert, J A; Sabol, J M; Tecotzky, M

1999-06-01

21

Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays  

Microsoft Academic Search

Both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry spectra from uranium oxide

1991-01-01

22

Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays  

Microsoft Academic Search

This paper reports that both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry

1991-01-01

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

Grazing Exit X-Ray Fluorescence Spectroscopy for Thin-Film Analysis  

Microsoft Academic Search

Under the grazing exit condition, X-ray fluorescence (XRF) experiments have been performed for metal thin films (Cu, Ni) on glass substrates. The XRF intensity was measured as a function of the exit angle for nearly normal X-ray incidence. The angular dependence of the grazing exit XRF intensity showed a sharp increase at the critical angle of Kalpha radiation for the

Takashi Noma; Hirokatsu Miyata; Shozo Ino

1992-01-01

25

Correcting for surface topography in X-ray fluorescence imaging.  

PubMed

Samples with non-planar surfaces present challenges for X-ray fluorescence imaging analysis. Here, approximations are derived to describe the modulation of fluorescence signals by surface angles and topography, and suggestions are made for reducing this effect. A correction procedure is developed that is effective for trace element analysis of samples having a uniform matrix, and requires only a fluorescence map from a single detector. This procedure is applied to fluorescence maps from an incised gypsum tablet. PMID:25343805

Geil, E C; Thorne, R E

2014-11-01

26

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

27

X-ray fluorescence analysis of various alloys. Part 1  

SciTech Connect

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

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

1980-02-15

28

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

29

Computer simulation of a backscattered x-ray fluorescence system.  

PubMed

An EGSnrc user code is developed to simulate a backscattered geometry in vivo x-ray fluorescence system for the measurement of platinum concentration in head and neck tumours. The user code is fundamentally based on a previous study which used the EGS4 Monte Carlo code. The new user code, which we have developed in this study, has new improvements which made it able to simulate the process of photon transportation through the different components of the modelled x-ray fluorescence system. The simulation process included modelling of the photon source, collimators, phantoms and detector. Simulation results were compared and evaluated against x-ray fluorescence data obtained experimentally from an existing system developed by the Swansea In vivo Analysis and Cancer Research Group. In addition, simulation results of this study were also compared with our previous study in which the EGS4 user code was used. Comparison between results has shown that the new EGSnrc user code was able to reproduce the spectral shape obtained using the experimental x-ray fluorescence system. The area under the Compton peak differs by 2.5% between the experimental measurement and the EGSnrc simulation. Similarly, the area under the two Pt K? peaks differs by 2.3% and 2.2%. PMID:25567407

Al-Ghorabie, Fayez H H

2015-01-01

30

Demonstration of x-ray fluorescence imaging of a high-energy-density plasmaa)  

NASA Astrophysics Data System (ADS)

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.

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

31

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

32

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

33

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

Microsoft Academic Search

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

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

2004-01-01

34

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

35

Use of handheld X-ray fluorescence spectrometry units for identification of arsenic in treated wood  

E-print Network

Use of handheld X-ray fluorescence spectrometry units for identification of arsenic in treated wood within preservative-treated wood. Abstract The objective of this study was to evaluate the performance of handheld XRF analyzers on wood that has been treated with a preservative containing arsenic. Experiments

Florida, University of

36

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

37

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

38

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

39

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

40

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

41

First X-ray Fluorescence MicroCT Results from Micrometeorites at SSRL  

SciTech Connect

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

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

2006-08-23

42

First X-ray Fluorescence MicroCT Results from Micrometeorites at SSRL  

SciTech Connect

X-ray fluorescence microCT (computed tomography) is a novel technique that allows non-destructive determination of the 3D distribution of chemical elements inside a sample. This is especially important in samples for which sectioning is undesirable either due to the risk of contamination or the requirement for further analysis by different characterization techniques. Developments made by third generation synchrotron facilities and laboratory X-ray focusing systems have made these kinds of measurements more attractive by significantly reducing scan times and beam size. First results from the x-ray fluorescence microCT experiments performed at SSRL beamline 6-2 are reported here. Beamline 6-2 is a 54 pole wiggler that uses a two mirror optical system for focusing the x-rays onto a virtual source slit which is then reimaged with a set of KB mirrors to a (2 x 4) {mu}m2 beam spot. An energy dispersive fluorescence detector is located in plane at 90 degrees to the incident beam to reduce the scattering contribution. A PIN diode located behind the sample simultaneously measures the x-ray attenuation in the sample. Several porous micrometeorite samples were measured and the reconstructed element density distribution including self-absorption correction is presented. Ultimately, this system will be used to analyze particles from the coma of comet Wild-2 and fresh interstellar dust particles both of which were collected during the NASA Stardust mission.

Ignatyev, Konstantin; Luening, Katharina; Brennan, Sean; Pianetta, Piero [Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Huwig, Kathy; Harvey, Ralph [Case Western Reserve University, Cleveland, OH 44106 (United States); Ishii, Hope; Bradley, John [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

2007-01-19

43

Composition characterization of combinatorial materials by scanning X-ray fluorescence microscopy using  

E-print Network

a fluorescence X-ray photon or an Auger electron. Thus, the energy of the fluorescence X-ray photon is equal is proportional to the number of excited atoms. Consequently, the mea- surement of an XRF spectrum quantifies) [8]. In characterizing combinatorial materials, we integrate both scanning XRF and X-ray diffraction

Engel, Jonathan

44

Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis  

SciTech Connect

We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. 'Demokritos,' Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current ({approx}{mu}A) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon K{alpha}. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented.

Sokaras, D. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Zarkadas, Ch. [PANalytical B.V., 7600 AA Almelo (Netherlands); Fliegauf, R.; Beckhoff, B. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Karydas, A. G. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Nuclear Spectrometry and Applications Laboratory, IAEA Laboratories, A-2444 Seibersdorf (Austria)

2012-12-15

45

Feasibility study of total reflection X-ray fluorescence analysis using a liquid metal jet X-ray tube  

NASA Astrophysics Data System (ADS)

Total reflection X-ray spectroscopy (TXRF) is a powerful analytical technique for qualitative and quantitative analysis of trace and ultratrace elements in a sample with lower limits of detection (LLDs) of pg/g to ng/g in concentration and absolute high fg levels are attainable. Several X-ray sources, from low power (few W), 18 kW rotating anodes to synchrotron radiation, are in use for the excitation and lead accordingly to their photon flux delivered on the sample the detection limits specified. Not only the power, but also the brilliance and focal shape are of importance for TXRF. A microfocus of 50-100 ?m spot size or the line focus of diffraction tubes is best suited. Excillum developed a new approach in the design of a source: the liquid metal jet anode. In this paper the results achieved with this source are described. A versatile TXRF spectrometer with vacuum chamber designed at Atominstitut was used for the experiments. A multilayer monochromator selecting the intensive Ga-K? radiation was taken and the beam was collimated by 50 ?m slits. Excellent results regarding geometric beam stability, high fluorescence intensities and low background were achieved leading to detection limits in the high fg range for Ni. A 100 mm2 silicon drift detector (SDD) collimated to 80 mm2 was used to collect the fluorescence radiation. The results from measurements on single element samples are presented.

Maderitsch, A.; Smolek, S.; Wobrauschek, P.; Streli, C.; Takman, P.

2014-09-01

46

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

47

Preparation of tissue samples for X-ray fluorescence microscopy  

NASA Astrophysics Data System (ADS)

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 technique. It enables the carrying out of investigations of the elemental composition of tissues even at the single cell level. The tissue samples for histopathological investigations are routinely fixed and embedded in paraffin. The authors try to verify the usefulness of such prepared tissue sections for elemental analysis with the use of X-ray fluorescence microscopy. Studies were performed on rat brain samples. Changes in elemental composition caused by fixation in formalin or paraformaldehyde and embedding in paraffin were examined. Measurements were carried out at the bending magnet beamline L of the Hamburger Synchrotronstrahlungslabor HASYLAB in Hamburg. The decrease in mass per unit area of K, Br and the increase in P, S, Fe, Cu and Zn in the tissue were observed as a result of the fixation. For the samples embedded in paraffin, a lower level of most elements was observed. Additionally, for these samples, changes in the composition of some elements were not uniform for different analyzed areas of rat brain.

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

2005-12-01

48

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

49

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

50

Feasibility of x ray fluorescence for spent fuel safeguards  

SciTech Connect

Quantifying the Pu content in spent nuclear fuel is necessary for many reasons, in particular to verify that diversion or other illicit activities have not occurred. Therefore, safeguarding the world's nuclear fuel is paramount to responsible nuclear regulation and public acceptance, but achieving this goal presents many difficulties from both a technical and economic perspective. The Next Generation Safeguards Initiative (NGSI) of NA-24 is funding a large collaborative effort between multiple laboratories and universities to improve spent nuclear fuel safeguards methods and equipment. This effort involves the current work of modeling several different nondestructive assay (NDA) techniques. Several are being researched, because no single NDA technique, in isolation, has the potential to properly characterize fuel assemblies and offer a robust safeguards measure. The insights gained from this research, will be used to down-select from the original set a few of the most promising techniques that complement each other. The goal is to integrate the selected instruments to create an accurate measurement system for fuel verification that is also robust enough to detect diversions. These instruments will be fabricated and tested under realistic conditions. This work examines one of the NDA techniques; the feasibility of using x ray emission peaks from Pu and U to gather information about their relative quantities in the spent fuel. X Ray Fluorescence (XRF), is unique compared to the investigated techniques in that it is the only one able to give the elemental ratio of Pu to U, allowing the possibility of a Pu gram quantity for the assembly to be calculated. XRF also presents many challenges, mainly its low penetration, since the low energy x rays of interest are effectively shielded by the first few millimeters of a fuel pin. This paper will explore the results of Monte Carlo N-Particle eXtended (MCNPX) transport code calculations of spent fuel x ray peaks. The MCNPX simulations will be benchmarked against measurements taken at Oak Ridge. Analysis of the feasibility of XRFs role in spent nuclear fuel safeguards efforts, particularly in the context of the overall NGSI effort will be discussed.

Freeman, Corey Ross [Los Alamos National Laboratory; Mozin, Vladimir [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory; Fensin, Michael L [Los Alamos National Laboratory; White, Julia M [Los Alamos National Laboratory; Croft, Stephen [Los Alamos National Laboratory; Stafford, Alissa [TAMU; Charlton, William [TAMU

2010-01-01

51

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

52

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

53

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

54

Resonant soft x-ray fluorescence studies of novel materials  

SciTech Connect

The authors are using resonant soft x-ray fluorescence at the Advanced Light Source to probe the electronic and geometric structure of novel materials. In the resonant process, a core electron is excited by a photon whose energy is near the core binding energy. In this energy regime the absorption and emission processes are coupled, and this coupling manifests itself in several ways. In boron nitride (BN), the resonant emission spectra reflect the influence of a ``spectator`` electron in an unoccupied excitonic state. The resonant emission can be used to distinguish between the various bulk phases of BN, and can also be used to probe the electronic structure of a monolayer of BN buried in a bulk environment, where it is inaccessible to electron spectroscopies. For highly-oriented pyrolytic graphite (HOPG) a coherent absorption-emission process takes place in the resonant regime, whereby crystalline momentum is conserved between the core excited electron and the valence hole which remains after emission.

Carlisle, J.A.; Terminello, L.J.; Hudson, E.A. [Lawrence Livermore National Lab., CA (United States); Shirley, E.L. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Jia, J.J.; Callcott, T.A. [Univ. of Tennessee, Knoxville, TN (United States); Himpsel, F.J. [IBM Research Div., Yorktown Heights, NY (United States). Thomas J. Watson Research Center; Ederer, D.L. [Tulane Univ., New Orleans, LA (United States); Perera, R.C.C. [Lawrence Berkeley Lab., CA (United States)

1995-02-08

55

Spray and gaseous jet diagnostics using x-ray-induced fluorescence imaging and flash radiography  

Microsoft Academic Search

The characterization of near nozzle dense sprays and axisymmetric gas jets using X-ray flash techniques is presented. Flash radiography and X-ray induced fluorescence imaging (X.I.F. imaging), using a flash X-ray developed at GREMI, offer two complementary diagnostics particularly efficient in high pressure conditions. In this work, a compact flash X-ray device is used to freeze fluid motions. Single shot radiographs

Laurent Hure; Eric Robert; Christophe Cachoncinlle; Raymond Viladrosa; Jean-Michel Pouvesle; Y. Michou; Iskender Gokalp

2001-01-01

56

Promising X-ray fluorescence tests for superconducting tunneljunction detector  

SciTech Connect

Scientists in the Physical Biosciences Division of the Ernest Orlando Berkeley National Laboratory (Berkeley Lab) studying transition metals in proteins with fluorescence-detected L-edge absorption spectroscopy have found the measurements to be extremely challenging. The difficulty is that the metal centers are present in very dilute concentrations so that their weak fluorescence is often obscured by strong background signals carbon and oxygen. To solve this problem, the Berkeley group has been working with researchers from the Advanced Detector Group at the Lawrence Livermore National Laboratory on an energy-dispersive superconducting tunnel junction x-ray detector. These devices in principle have the energy resolution needed to reveal the metal signal. The most recent results with the latest version of the detector on Beamline 4.0.1-2 at the Advanced Light Source (ALS) illustrate the promise of the cryogenic detector strategy not only for this application but also for spectroscopy of other types of dilute samples. Transition-metal complexes are key elements in many biologically important processes that are catalyzed by proteins (enzymes), photosynthesis being a prime example. The changes in that occur in electronic structure throughout a catalytic cycle are the subject of much research aimed at understanding the mechanisms of these processes. L-edge x-ray spectroscopy offers several advantages relative to the more common K-edge techniques, since it involves allowed transitions to the d-orbitals associated with metal-ligand bonding. It also has a rich multiplet structure interpretable by theory and higher spectral resolution.

Friedrich, Stephan; Robinson, Arthur L.

2001-05-15

57

Synchrotron X-ray experiments in pulsed high magnetic fields.  

PubMed

Recent developments of the techniques for measurements of X-ray diffraction and X-ray absorption spectroscopy in very high magnetic fields are reviewed. Miniature pulsed magnets allow us to conduct various kinds of high-field X-ray experiments rather easily; the magnets can be readily installed on a conventional apparatus such as a diffractometer and a cryostat because of its smallness. The results of some experiments on the field-induced phase transition of a rare-earth intermetallic compound (YbInCu4) are also presented. PMID:18187843

H Matsuda, Yasuhiro

2008-01-01

58

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

59

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

60

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

61

Analysis of trace Co in synthetic diamonds using synchrotron radiation excited X-ray fluorescence analysis  

Microsoft Academic Search

Synchrotron radiation excited X-ray fluorescence analysis was utilized for characterization of trace impurities in synthetic diamonds. Advantage of the energy tunability was fully utilized to evaluate the attenuation of X-rays through the sample, and the absorption corrected X-ray fluorescence yield was utilized for quantitative analysis. Diamonds grown with several types of metallic solvents were investigated, and quantitative analysis of trace

Shinjiro Hayakawa; Xiao-Peng Jia; Masao Wakatsuki; Yohichi Gohshi; Takeshi Hirokawa

2000-01-01

62

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

PubMed

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

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

2013-11-14

63

Advances in X-Ray Chemical Analysis, Japan, 41 (2010) ISSN 0911-7806 Portable Total Reflection X-Ray Fluorescence Spectrometer  

E-print Network

Advances in X-Ray Chemical Analysis, Japan, 41 (2010) ISSN 0911-7806 © X Portable Total Reflection X-Ray Fluorescence Spectrometer for Ultra Trace Elemental Determination Shinsuke KUNIMURA and Jun KAWAI #12;#12;41 29 X Adv. X-Ray. Chem. Anal., Japan 41, pp.29-44 (2010) 606-8501 X Portable Total

Jun, Kawai

64

An improved double fluorescence detector for fluorescence EXAFS (Extended X-ray Absorption Fine Structure) measurements  

SciTech Connect

In many cases the fluorescence EXAFS signal is contaminated with fluorescence from nearby elements. If this fluorescence is of lower energy than the element of interest, x-ray filters are not effective. One method for dealing with this problem is the double fluorescence method described by Wong and Rao. This paper describes an improved version of this double fluorescence scheme which greatly improves its efficiency. Data are presented for a sample of 1/2% Hf in Ni/sub 3/Al, and 1.6% CuO in NiO. When standard fluorescence is used, both signals are almost completely obscured by the approx. =100X larger Ni K fluorescence signal. With the double fluorescence detector the Hf L/sub 3/ and Cu K-edge signals are clearly observed and good spectra can be obtained in about an hour. 4 refs., 4 figs.

Heald, S.M.

1988-01-01

65

Continuous Flow Cryostat for X-Ray Fluorescence  

SciTech Connect

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

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

2010-06-23

66

Portable x-ray fluorescence spectrometer. Innovative technology summary report  

SciTech Connect

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

NONE

1998-12-01

67

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

68

Spray and gaseous jet diagnostics using x-ray-induced fluorescence imaging and flash radiography  

NASA Astrophysics Data System (ADS)

The characterization of near nozzle dense sprays and axisymmetric gas jets using X-ray flash techniques is presented. Flash radiography and X-ray induced fluorescence imaging (X.I.F. imaging), using a flash X-ray developed at GREMI, offer two complementary diagnostics particularly efficient in high pressure conditions. In this work, a compact flash X-ray device is used to freeze fluid motions. Single shot radiographs of argon jets and water sprays expanding in ambient air have been performed. Radial density profiles were measured and quantitative density measurements have been extracted for argon, nitrogen-argon mixture and water jets, using flash X-ray radiography. UV fluorescence emissions due to X-ray excitation of the jet species were imaged on a gated intensified CCD camera.

Hure, Laurent; Robert, Eric; Cachoncinlle, Christophe; Viladrosa, Raymond; Pouvesle, Jean-Michel; Michou, Y.; Gokalp, Iskender

2001-04-01

69

Theory and analysis of soft x-ray laser experiments  

SciTech Connect

The atomic modeling of soft x-ray laser schemes presents a formidable challenge to the theorists - a challenge magnified by the recent successful experiments. A complex plasma environment with many ion species present must be simulated. Effects such as turbulence, time dependence, and radiation transport, which are very difficult to model accurately, may be important. We shall describe our efforts to model the recently demonstrated soft x-ray laser in collisionally pumped neon-like selenium, with emphasis on the ionization balance and excited state kinetics. The relative importance of various atomic processes, such as collisional excitation and dielectronic recombination, on the inversion kinetics will be demonstrated. We shall compare our models with experimental results and evaluate the success of this technique in predicting and analyzing the results of x-ray laser experiments. 22 refs., 5 figs., 3 tabs.

Whitten, B.L.; Hazi, A.U.

1985-10-01

70

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...

71

Application of confocal X-ray fluorescence micro-spectroscopy to the investigation of paint layers.  

PubMed

A confocal micro X-ray fluorescence (MXRF) spectrometer based on polycapillary X-ray optics was used for the identification of paint layers. The performance of the confocal MXRF was studied. Multilayered paint fragments of a car were analyzed nondestructively to demonstrate that this confocal MXRF instrument could be used in the discrimination of the various layers in multilayer paint systems. PMID:25151613

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

2014-12-01

72

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

73

A furnace to 1200 K for in situ heating x-ray diffraction, small angle x-ray scattering, and x-ray absorption fine structure experiments  

NASA Astrophysics Data System (ADS)

A furnace with a water-cooled outside shell has been assembled to do in situ x-ray diffraction (XRD), small angle x-ray scattering (SAXS), and x-ray absorption fine structure (XAFS) experiments. The details of the furnace are described in this paper. The in situ XRD, SAXS, and XAFS experiments during the heating process demonstrate that the available temperature range of this furnace is from room temperature to 1200 K with a temperature accuracy of ±0.1 K. By using this furnace, in situ XRD, SAXS, and XAFS experimental techniques with temperature change can be easily combined together.

Cai, Quan; Wang, Qiang; Wang, Wei; Mo, Guang; Zhang, Kunhao; Cheng, Weidong; Xing, Xueqing; Chen, Zhongjun; Wu, Zhonghua

2008-12-01

74

SIXE: An X-ray experiment for a minisatellite  

SciTech Connect

SIXE (Spanish Italian X-ray Experiment) is an X-ray detector with geometric area of 2300 cm{sup 2}, formed by four identical gas-filled Multicell Proportional Counters, and devoted to study the long term spectroscopy of selected X-ray sources in the energy range 3-50 keV. The main characteristics of SIXE are: time accuracy of 1 microsecond, spectral resolution of 5% for E>35 keV and 46/{radical}(E)% for E<35 keV, continuum sensitivity (3{sigma} in 10{sup 5} s) of 2x10{sup -6} ph/cm{sup 2}{center_dot}s{sup -1}{center_dot}keV{sup -1}, and line sensitivity (3{sigma} in 10{sup 5} s) of 8x10{sup -6} ph/cm{sup 2}{center_dot}s{sup -1}. The size of the instruments and the requirements of the payload (weight 103 kg, full dimensions 660x660x450 mm{sup 3}, power budget <60 W, on-board memory 2 Gbits, telemetry rate <100 kbps) make this experiment fully compatible with a minisatellite mission. The experiment, whose feasibility study has just been finished, has been proposed for flying on the Spanish MINISAT-02 satellite, in a 3 years long mission starting about 2002-2004. The main scientific goal is the study of the short and long term variability of a selected set of X-ray sources, such as quasars, Seyfert galaxies, high and low mass X-ray binaries, etc. The philosophy of the mission will provide the unique opportunity for the study of X-ray sources with a temporal accuracy of 1 microsecond all through the time range 10{sup -5}:10{sup 7} s.

Isern, Jordi; Hernanz, Margarida [Institut d'Estudis Espacials de Catalunya (IEEC), Gran Capita 2-4, 08034 Barcelona (Spain); Consejo Superior de Investigaciones Cientificas (CSIC) (Spain); Bravo, Eduardo; Garcia-Berro, Enrique; Gutierrez, Jordi; Jose, Jordi; Garcia-Senz, Domingo; Cabestany, Joan; Madrenas, Jordi [Institut d'Estudis Espacials de Catalunya (IEEC), Gran Capita 2-4, 08034 Barcelona (Spain); Universitat Politecnica de Catalunya (UPC), Barcelona (Spain); Gomez-Gomar, Jordi [Institut d'Estudis Espacials de Catalunya (IEEC), Gran Capita 2-4, 08034 Barcelona (Spain); Giovannelli, Franco; La Padula, Cesare D. [Instituto di Astrofisica Spaziale (IAS-CNR), Frascati (Italy); Sabau, Lola; Angulo, Manuel; Fernandez-Valbuena, Manuel; Herrera, Erardo; Reina, Manuel; Talavera, Antonio [Instituto Nacional de Tecnica Aervespacial (INTA), Torrejon de Ardoz (Spain); Bausells, Joan [Centro Nacional de Microelectroonica (CNM, IMB-CSIC), Bellaterra (Spain)

1999-12-15

75

The X-ray Telescope of the CAST Experiment  

E-print Network

The CERN Axion Solar Telescope (CAST) searches for solar axions employing a 9 Tesla superconducting dipole magnet equipped with 3 independent detection systems for X-rays from axion-photon conversions inside the 10 m long magnetic field. Results of the first 6 months of data taking in 2003 imply a 95 % CL upper limit on the axion-photon coupling constant of 1.16x10(-10) GeV(-1) for axion masses CAST is a X-ray telescope consisting of a Wolter I type mirror system and a fully depleted pn-CCD as focal plane detector. Exploiting the full potential of background suppression by focussing X-rays emerging from the magnet bore, the axion sensitivity obtained with telescope data taken in 2004, for the first time in a controlled laboratory experiment, will supersede axion constraints derived from stellar energy loss arguments.

R. Kotthaus; H. Braeuninger; P. Friedrich; R. Hartmann; D. Kang; M. Kuster; G. Lutz; L. Strueder

2005-11-14

76

(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

77

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

78

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

79

Uranium and plutonium solution assays by transmission-corrected x-ray fluorescence  

Microsoft Academic Search

We have refined and tested a previously developed x-ray fluorescence analysis technique for uranium and plutonium solutions that compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays. We use ⁵⁷Co to efficiently excite the K lines of the elements, and a mixed ⁵⁷Co plus ¹⁵³Gd transmission source to correct for variations in absorption. The absorption

R W Ryon; W D Ruhter; V Rudenko; A Sirontinin; A A Petrov

1999-01-01

80

Determination of ultratrace concentrations of uranium and thorium in natural waters by x-ray fluorescence  

Microsoft Academic Search

An x-ray fluorescence method for the simultaneous determination of uranium and thorium at the less than 1 ppM level in natural waters is described. Uranium and thorium are coprecipitated with an internal standard, yttrium, and incorporated into an iron-aluminum hydroxide carrier. The hydroxide precipitate is filtered, and the filter disk is analyzed by the energy-dispersive x-ray fluorescence technique. Matrix interferences

J. H. Jr. Stewart; R. D. Brooksbank

1981-01-01

81

Effect of x-ray beamline optics on x-ray photon correlation spectroscopy experiments.  

SciTech Connect

We have evaluated the applicability of vertically-focusing kinoform lenses for tailoring the vertical coherence length of storage-ring undulator x-ray beams so that the entirety of the coherent flux can be used for small angle multi-speckle x-ray photon correlation spectroscopy (XPCS) experiments. We find that the focused beam produced by a kinoform lens preserves the coherence of the incident unfocused beam and that at an appropriate distance downstream of the focus, the diverging beam produces speckles nearly identical to those produced by an equivalently-sized unfocused beam. We have also investigated the effect of imperfect beamline optics on the observed coherence properties of the beam. Via phase contrast imaging and beam-divergence measurements, we find that a horizontally-deflecting mirror in our beamline precludes us from seeing the true radiation source point but instead acts as an apparent source of fixed size at the center of our insertion device straight section. Finally, we discuss how expected near-future optimization of these optics will greatly benefit XPCS measurements performed at beamline 8-ID-I at the Advanced Photon Source.

Sandy, A. R.; Evans-Lutterodt, K.; Fezzaa, K.; Kim, S.; Narayanan, S.; Sprung, M.; Stein, A.; X-Ray Science Division; BNL; Gwangiu Inst. of Science and Technology

2007-01-01

82

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

83

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

PubMed

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

2014-09-01

84

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

85

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

SciTech Connect

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

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

2005-06-15

86

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

NASA Astrophysics Data System (ADS)

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

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

2005-06-01

87

A microfocus X-ray fluorescence beamline at Indus-2 synchrotron radiation facility.  

PubMed

A microfocus X-ray fluorescence spectroscopy beamline (BL-16) at the Indian synchrotron radiation facility Indus-2 has been constructed with an experimental emphasis on environmental, archaeological, biomedical and material science applications involving heavy metal speciation and their localization. The beamline offers a combination of different analytical probes, e.g. X-ray fluorescence mapping, X-ray microspectroscopy and total-external-reflection fluorescence characterization. The beamline is installed on a bending-magnet source with a working X-ray energy range of 4-20 keV, enabling it to excite K-edges of all elements from S to Nb and L-edges from Ag to U. The optics of the beamline comprises of a double-crystal monochromator with Si(111) symmetric and asymmetric crystals and a pair of Kirkpatrick-Baez focusing mirrors. This paper describes the performance of the beamline and its capabilities with examples of measured results. PMID:23412498

Tiwari, M K; Gupta, P; Sinha, A K; Kane, S R; Singh, A K; Garg, S R; Garg, C K; Lodha, G S; Deb, S K

2013-03-01

88

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

89

Development of an x-ray generator using a pyroelectric crystal for x-ray fluorescence analysis on planetary landing missions  

NASA Astrophysics Data System (ADS)

The chemical element abundance on planetary surface is essential for planetary science. We have been developing an active X-ray spectrometer (AXS), which is an in-situ chemical element analyzer based on the X-ray florescence analysis for future planetary landing missions. The AXS consists of an X-ray detector and multiple X-ray sources. Although a pyroelectric X-ray generator is promising for the AXS as an X-ray source, the raise of emission X-ray intensity is necessary for short-time and precise determination of elemental composition. Also, in order to enhance the detection efficiency of light major elements such as Mg, Al, and Si, we have tested the low energy X-ray emission by changing the target material. In this study, the X-ray emission calculation at the target by Monte Carlo simulation and the X-ray emission experiments were carried out. More than 106 cps of the time-averaged X-ray emission rate was achieved in maximum using a LiTaO3 crystal with 4 mm thickness and Cu target with 10 um thickness. The performance of pyroelectric X-ray generator is presented in this paper.

Kusano, Hiroki; Oyama, Yuki; Naito, Masayuki; Nagaoka, Hiroshi; Kuno, Haruyoshi; Shibamura, Eido; Hasebe, Nobuyuki; Amano, Yoshiharu; Kim, Kyeong J.; Matias Lopes, José A.

2014-09-01

90

Portable x-ray fluorescence spectrometer for coating thickness measurement  

SciTech Connect

A handheld x-ray spectrometer has been realized and tested. The purpose of the device is to measure the thickness of coated samples in the range of 1-1500 nm in an industrial environment. Accuracy of {approx}3% has been achieved in this range with a measurement time of 1 min. Automated software has been implemented to allow utilization by a nonspecialist operator. An automated calibration procedure, based on measurements of reference samples, is used.

Carapelle, Alain; Fleury-Frenette, Karl; Collette, Jean-Paul; Garnir, Henri-Pierre; Harlet, Philippe [Centre Spatial de Liege (CSL), University of Liege, Avenue de Pre-Ally, Liege Science Park, 4031 Angleur (Belgium); Institut de Physique Nucleaire, Atomique et de Spectroscopie (IPNAS), University of Liege, 15 Allee du Six Aout, Sart Tilman, 4031 Angleur (Belgium); Arcelor-Mittal Research Liege, Boulevard de Colonster, B57, 4000 Liege (Belgium)

2007-12-15

91

A tube-excited x-ray fluorescence spectrometer for use in small-diameter boreholes  

SciTech Connect

A portable in-situ x-ray fluorescence analytical system that uses an x-ray tube excitation source and a cooled Si(Li) spectrometer for detecting characteristic emission x rays has been developed for use in small-diameter wells and boreholes. The 15-watt, iron-anode x-ray tube operates up to 30 kV. Three wells at the Sandia National Laboratory Chemical Waste Landfill, lined with 76 {mu} thick polyethylene, were logged specifically for Cr contamination. Detection limits below 50 ppM were achieved with counting intervals of 600 seconds and with the Si(Li) detector operating at 450-eV resolution (full width at half maximum [FWHM] for the Mn K-alpha x ray).

Reeves, J.H.; Arthur, R.J.; Brodzinski, R.L.; Shepard, C.L.

1995-04-01

92

Laser Synchrotron Source Experiment for Tunable Monochromatic X-rays  

Microsoft Academic Search

The Laser Synchrotron Source (LSS) experiment at the Naval Research Laboratory has generated monochromatic, tunable x-rays by Thomson backscattering of laser photons from a relativistic electron beam[1]. Laser photons from a 5 J, 10 nsec Nd:Glass laser at 1.053 mum wavelength are backscattered from a 4 MeV, 300 mA electron beam generated by a one and a half cell S-band

R. P. Fischer; A. Ting; C. I. Moore; P. Sprangle; M. Baine; R. Elton; S. Ride

2000-01-01

93

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

94

Ultrahigh vacuum-compatible fluorescence x-ray absorption fine structure detector  

NASA Astrophysics Data System (ADS)

The design and operation of an ultrahigh vacuum (UHV) compatible ionization chamber for fluorescent x-ray detection in the hard-x-ray regime is described. The detector is comprised of two main components: an UHV compatible, bakeable housing and multiple, 90% transparent, nickel wire-mesh internal collectors. The detector has been used successfully to study molecular beam epitaxy prepared metal thin films in situ.

Gordon, R. A.; Crozier, E. D.; Shoults, J.; Jiang, D.-T.

2002-08-01

95

Quantitative X-ray fluorescence analysis of an Egyptian faience pendant and comparison with PIXE.  

PubMed

The X-ray fluorescence (XRF) technique is a common choice in the archaeometric field for in situ investigations with portable instruments. This work shows that XRF portable systems can be used for quantitative analyses using appropriate software, obtaining a similar accuracy to that provided with other techniques such as particle-induced X-ray emission (PIXE), as shown for an Egyptian faience pendant and for two glass standards. PMID:19636540

de Viguerie, L; Duran, A; Bouquillon, A; Solé, V A; Castaing, J; Walter, P

2009-12-01

96

The cosmic X-ray experiment aboard HEAO-1  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

97

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

98

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

99

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

100

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

NASA Astrophysics Data System (ADS)

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

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

2002-01-01

101

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

PubMed Central

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. PMID:21721815

Cong, Wenxiang; Shen, Haiou; Wang, Ge

2011-01-01

102

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

103

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

104

Method for determining the modulation transfer function of X-ray fluorescence mapping system.  

PubMed

A method for determining the modulation transfer function (MTF) in direct X-ray fluorescence mapping (XFM) system is reported. With a standard container filled with homogeneous gold nanoparticle (GNP) solution (1% by weight), sharp edges are made and utilized to acquire the data for edge spread function (ESF). Through necessary data processing such as signal extraction, attenuation correction and curve fitting and proper calculations of differentiating and Fourier transform, MTF can be determined. Influencing factors of MTF determination in XFM system are thoroughly discussed in theory and validated by experiments. The results show that different mapping steps do not noticeably affect the measured MTF, while MTF is greatly degraded as the collimator-to-object distance increases. The theoretical analyses and experimental validations of the MTF determination are useful and helpful for imaging performance evaluation, system design and optimal operations. The presented methodology could be applied in other XRF based systems with modified imaging trajectories. PMID:25321501

Ren, Liqiang; Zhou, Zhongxing; Ghani, Muhammad U; Li, Yuhua; Liu, Hong

2014-09-01

105

The MicroAnalysis Toolkit: X-ray Fluorescence Image Processing Software  

SciTech Connect

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

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

2011-09-09

106

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

SciTech Connect

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

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

2007-08-08

107

Probing the graphite band structure with resonant soft-x-ray fluorescence  

SciTech Connect

For incident photon energies near the core binding energy, inelastic x-ray scattering theory predicts a coherent absorption-emission process in which crystal momentum is conserved. Momentum conservation should manifest itself as dispersive features in fluorescence spectra. We report the detection of such features for the first time in graphite, and show that there exists a clear relationship between them and the graphite band structure. Our results demonstrate the potential of resonant soft-x-ray fluorescence for examining the momentum-resolved electronic structure of complex materials.

Carlisle, J.A.; Shirley, E.L.; Hudson, E.A.; Terminello, L.J.; Callcott, T.A.; Jia, J.J.; Ederer, D.L.; Perera, R.C.C.; Himpsel, F.J. (Lawrence Livermore National Laboratory, Livermore, California 94551 (United States) University of Tennessee, Knoxville, Tennessee 37996 (United States) Tulane Unviersity, New Orleans, Louisiana 70118 (United States) Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States) IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States))

1995-02-13

108

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

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

Soft x-ray laser experiments at Novette Laser Facility  

SciTech Connect

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

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

1984-03-05

111

Influence of X-ray tube spectral distribution on uncertainty of calculated fluorescent radiation intensity  

NASA Astrophysics Data System (ADS)

The relative radiation intensity ( Ri) defined as fluorescent radiation intensity of analyte in specimen to fluorescent radiation intensity of pure element or compound, e.g., oxide is used in calculation in both fundamental parameter methods and in theoretical influence coefficient algorithms. Accuracy of calculated Ri is determined by uncertainties of atomic parameters, spectrometer geometry and also by X-ray tube spectral distribution. This paper presents the differences between Ri calculated using experimental and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al., Ebel, and Finkelshtein-Pavlova. The calculations are performed for the most common targets, i.e., Cr, Mo, Rh and W. In this study, Ri is calculated for V, Cr, Mn, Fe, Co, Ni, Cu and Mo in steels as an example. The differences between Ri calculated using different X-ray tube spectrum algorithms are presented when pure element standard, multielement standard similar to the analyzed material and one pure element standard for all analytes is used in X-ray fluorescence analysis. The differences between Ri for intermediate-thickness samples (and also for thin films) and for X-ray tube, which ran for many hours, are also evaluated.

Sitko, Rafa?

2007-08-01

112

A Laboratory-Scale Coaxial Fluorescence and Soft X-ray Microscope for Biological Observation  

NASA Astrophysics Data System (ADS)

A laboratory-scale coaxial fluorescence and soft x-ray microscope for biological observation was developed. The characteristic features of a fluorescence microscope were introduced to the conventional soft x-ray microscope, which was developed in our previous study, where the specimens can be set in air. One of the technical difficulties in detecting visible fluorescence is the chromatic aberration. This was overcome by applying a reflective optics, Wolter mirror, to the coaxial optical system. The coaxial optical system offers experimental simplicity and makes it possible to obtain soft x-ray images and fluorescence images of an identical specimen, which can be more informative than applying either imaging modality alone. Therefore, the newly developed optical system offers high-quality structural and morphological details of biological specimens with the ability to localize specific cells and other important sub-cellular targets. Soft x-ray images and fluorescence images of an identical DNA, which were derived from redfish testes and stained with DAPI (4', 6-diamidino-2-phenylindole), were obtained by the newly developed coaxial optical system.

Takaba, K.; Aoki, S.

2011-09-01

113

OBSERBATION OF HIGH INTENSITY X-RAYS IN INVERSE COMPTON SCATTERING EXPERIMENT  

E-print Network

OBSERBATION OF HIGH INTENSITY X-RAYS IN INVERSE COMPTON SCATTERING EXPERIMENT S. Kashiwagi, M the first results of high intensity x-ray generation using Inverse Laser Compton scattering. This experiment Facility (ATF) in September 1999.The ATF is an accelerator and beam physics user facility. The 3.5 ps x-ray

114

Apollo 16 Experiments - Fluorescence Spectrometer  

NSDL National Science Digital Library

This page, from the Lunar and Planetary Institute, describes how the composition of portions of the lunar surface was determined by observing the fluorescence produced by solar x-rays. Images are provided with results from the experiments and links are offered to other LPI pages with information on the Apollo missions. This page is written at the level of introductory physics.

2009-07-29

115

X-ray fluorescence spectrometry for high throughput analysis of atmospheric aerosol samples: The benefits of synchrotron X-rays  

NASA Astrophysics Data System (ADS)

The determination of trace element mass concentrations in ambient air with a time resolution higher than one day represents an urgent need in atmospheric research. It involves the application of a specific technique both for the aerosol sampling and the subsequent analysis of the collected particles. Beside the intrinsic sensitivity of the analytical method, the sampling interval and thus the quantity of collected material that is available for subsequent analysis is a major factor driving the overall trace element detection power. This is demonstrated for synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) of aerosol samples collected with a rotating drum impactor (RDI) in hourly intervals and three particle size ranges. The total aerosol mass on the 1-h samples is in the range of 10 µg. An experimental detection of the nanogram amounts of trace elements with the help of synchrotron X-rays was only achievable by the design of a fit-for-purpose sample holder system, which considered the boundary conditions both from particle sampling and analysis. A 6-µm polypropylene substrate film has evolved as substrate of choice, due to its practical applicability during sampling and its suitable spectroscopic behavior. In contrast to monochromatic excitation conditions, the application of a 'white' beam led to a better spectral signal-to-background ratio. Despite the low sample mass, a counting time of less than 30 s per 1-h aerosol sample led to sufficient counting statistics. Therefore the RDI-SR-XRF method represents a high-throughput analysis procedure without the need for any sample preparation. The analysis of a multielemental mass standard film by SR-XRF, laboratory-based wavelength-dispersive XRF spectrometry and laboratory-based micro XRF spectrometry showed that the laboratory-based methods were no alternatives to the SR-XRF method with respect to sensitivity and efficiency of analysis.

Bukowiecki, Nicolas; Lienemann, Peter; Zwicky, Christoph N.; Furger, Markus; Richard, Agnes; Falkenberg, Gerald; Rickers, Karen; Grolimund, Daniel; Borca, Camelia; Hill, Matthias; Gehrig, Robert; Baltensperger, Urs

2008-09-01

116

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

117

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

PubMed Central

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

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

2014-01-01

118

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

SciTech Connect

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

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

2009-01-01

119

Determination of trace elements in uranium oxide by Total Reflection X-ray Fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

A study on the applicability of Total Reflection X-ray Fluorescence for the determination of multielements in trace amounts in U 3O 8 matrix has been made. The calibration of the Total Reflection X-ray Fluorescence spectrometer and the validation of the method were done using multielement standards. The trace elements present in U 3O 8 standards and samples were determined after separating the U matrix by solvent extraction using tri- n-butyl phosphate and trioctyl phosphine oxide as extractants. From the aqueous phase the elements K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr, Y, Zr, Pb and Ba, etc., were determined by Total Reflection X-ray Fluorescence using Ga as an internal standard. An intercomparison of the Total Reflection X-ray Fluorescence determined concentrations of the trace elements specific to nuclear fuel, e.g. Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn in U 3O 8 standards/samples with certified concentrations for these elements in U 3O 8 standards and Inductively Coupled Plasma Atomic Emission Spectroscopy determined concentrations in real U 3O 8 samples was also made. The method shows a precision and accuracy better than 5% (1 ?) for most elements in concentration range of ng/mL with a sample size of 10 ?L.

Misra, N. L.; Singh Mudher, K. D.; Adya, V. C.; Rajeswari, B.; Venugopal, V.

2005-07-01

120

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...

121

Radiochemical Analysis by High Sensitivity Micro X-Ray Fluorescence Detection  

SciTech Connect

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

Ning Gao

2006-05-12

122

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

123

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

124

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...

125

Determination of Fe and Zn in healing plants by radionuclide X-ray fluorescence analysis  

Microsoft Academic Search

Radionuclide X-ray fluorescence method was used for the determination of Fe and Zn in healing plants (Sage, Peppermint, Stinging,\\u000a Common Agrimony, Milfoil, Ribwort, Tansy, White Dead-Nettle).238Pu exciting source and Si\\/Li semiconductor detector were used for the determination.

M. Harangozó; J. Tölgyessy; O. Tome?ek; I. Ruži?ka; K. Cejpek

1999-01-01

126

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...

127

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...

128

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 ...

129

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

USGS Publications Warehouse

Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 ??g of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods. ?? 1969.

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

1969-01-01

130

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...

131

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 ...

132

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

NASA Astrophysics Data System (ADS)

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

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

133

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

134

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

SciTech Connect

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

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

1996-12-01

135

Photon Regeneration Experiment for Axion Search Using X-Rays  

SciTech Connect

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

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

2010-12-17

136

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

137

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

138

An ultrahigh vacuum goniometer system equipped with a Si(Li) array detector for soft x-ray standing-wave experiments  

NASA Astrophysics Data System (ADS)

An ultrahigh vacuum compatible goniometer system has been developed for use in angle-scan standing-wave experiments in a soft x-ray region. This system uses a horizontal two-axis (theta and two-theta) goniometer for the x-ray diffractometer. The theta axle used for sample rotations is inserted into the vacuum chamber through a differentially pumped rotary feedthrough and is driven by a stepping motor. To detect x-ray fluorescence excited by x-ray standing waves, a three-element linear-array Si(Li) detector is equipped for this system. SK? fluorescence angular yield from monolayer-order sulfur atoms on a GaAs(111) surface could be measured for the first time by the angle-scan standing-wave experiment. This result demonstrates that this goniometer system can be used for angle-scan standing-wave experiments in the soft x-ray region.

Maeyama, Satoshi; Kawamura, Tomoaki; Oshima, Masaharu

1991-12-01

139

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

140

Origin of dark-channel X-ray fluorescence from transition-metal ions in water.  

PubMed

The nonradiative dark channels in the L-edge fluorescence spectra from transition-metal aqueous solution identify the ultrafast charge-transfer processes playing an important role in many biological and chemical systems. Yet, the exact origin of such spectral dips with respect to the X-ray transmission spectrum has remained unclear. In the present study we explore the nature of the underlying decay mechanism of 2p core-excited Co(2+) in water by probing the nonradiative Auger-type electron emission channel using photoelectron spectroscopy from a liquid microjet. Our measurements demonstrate unequivocally that metal-to-water charge transfer quenches fluorescence and will inevitably lead to a dip in the total-fluorescence-yield X-ray absorption spectrum. This is directly revealed from the resonant enhancement of valence signal intensity arising from the interference of two identical final states created by a direct and Auger-electron emission, respectively. PMID:22175947

Seidel, Robert; Ghadimi, Samira; Lange, Kathrin M; Bonhommeau, Sébastien; Soldatov, Mikhail A; Golnak, Ronny; Kothe, Alexander; Könnecke, René; Soldatov, Alexander; Thürmer, Stephan; Winter, Bernd; Aziz, Emad F

2012-01-25

141

Correction method for self-absorption effects of fluorescence x-ray absorption near-edge structure on multilayer samples  

NASA Astrophysics Data System (ADS)

It is well known that fluorescence x-ray absorption spectroscopy suffers from the self-absorption effects for thick and concentrated samples. In this study, a simple correction method is provided for correcting the self-absorption effects of fluorescence x-ray absorption near edge structure (XANES) spectrum for multilayer samples. This method is validated by application on fluorescence XANES spectra for a Cr/C multilayer measured at different incidence angles. The errors produced by the self-absorption effects for the measured fluorescence x-ray absorption spectra without corrections are also estimated and discussed.

Li, Wen-bin; Yuan, Xiao-feng; Zhu, Jing-tao; Zhu, Jie; Wang, Zhan-shan

2015-01-01

142

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

143

Total reflection X-ray fluorescence and energy-dispersive X-ray fluorescence analysis of runoff water and vegetation from abandoned mining of Pb Zn ores  

NASA Astrophysics Data System (ADS)

The present work reports on the heavy metal content: Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in running waters and vegetation around abandoned mining areas. Two species of mosses ( Dicranum sp. and Pleurocarpus sp.) and three different species of wild grass ( Bromus sp., Rumex sp. and Pseudoavena sp.) growing on the surrounding areas of old lead-zinc mines (Aran Valley, Pyrenees, NE Spain) have been analyzed. Both water and vegetation were collected in two different sampling places: (a) near the mine gallery water outlets and (b) on the landfill close to the abandoned mineral concentration factories. For the heavy metal content determination, two different techniques were used: total reflection X-ray fluorescence for water analysis and energy-dispersive X-ray fluorescence for vegetation study. Surface waters around mine outlets exhibit anomalous content of Co, Ni, Zn, Cd. Stream waters running on mining landfills exhibit higher Cu, Zn, Cd and Pb than those of the waters at the mine gallery outlets. The results allow us to assess the extent of the environmental impact of the mining activities on the water quality. The intake of these elements by vegetation was related with the sampling place, reflecting the metal water content and the substrate chemistry. Accumulation of metals in mosses is higher than those exhibited in wild grasses. Furthermore, different levels of accumulation were found in different wild grass. Rumex sp. presented the lowest metal concentrations, while Pseudoavena sp. reported the highest metal content.

Marques, A. F.; Queralt, I.; Carvalho, M. L.; Bordalo, M.

2003-12-01

144

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-contaminating metal cations (Cu, Zn, & Cr) in the solid phase speciation of arsenic. Elemental maps from ÝSXRF of this study show that As solid phase speciation is dependent on the co-contaminating metal cation fraction

Sparks, Donald L.

145

Advances in X-Ray Chemical Analysis, Japan, 45 (2014) ISSN 0911-7806 Role of Desktop X-Ray Fluorescence Analysis of Wakayama  

E-print Network

of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606-8501, Japan (Received 25 October widely known but desk-top type X-ray fluorescence analysis was performed for the forensic analysis curry poisoning case, Identification, Forensic analysis, Arsenic 1998 10 7 25 X Si Ca Ba Si Ca X 1. 1998

Jun, Kawai

146

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...

147

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

148

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

149

Probing the graphite band structure with resonant soft-x-ray fluorescence  

SciTech Connect

Soft x-ray fluorescence (SXF) spectroscopy using synchrotron radiation offers several advantages over surface sensitive spectroscopies for probing the electronic structure of complex multi-elemental materials. Due to the long mean free path of photons in solids ({approximately}1000 {angstrom}), SXF is a bulk-sensitive probe. Also, since core levels are involved in absorption and emission, SXF is both element- and angular-momentum-selective. SXF measures the local partial density of states (DOS) projected onto each constituent element of the material. The chief limitation of SXF has been the low fluorescence yield for photon emission, particularly for light elements. However, third generation light sources, such as the Advanced Light Source (ALS), offer the high brightness that makes high-resolution SXF experiments practical. In the following the authors utilize this high brightness to demonstrate the capability of SXF to probe the band structure of a polycrystalline sample. In SXF, a valence emission spectrum results from transitions from valence band states to the core hole produced by the incident photons. In the non-resonant energy regime, the excitation energy is far above the core binding energy, and the absorption and emission events are uncoupled. The fluorescence spectrum resembles emission spectra acquired using energetic electrons, and is insensitive to the incident photon`s energy. In the resonant excitation energy regime, core electrons are excited by photons to unoccupied states just above the Fermi level (EF). The absorption and emission events are coupled, and this coupling manifests itself in several ways, depending in part on the localization of the empty electronic states in the material. Here the authors report spectral measurements from highly oriented pyrolytic graphite.

Carlisle, J.A.; Shirley, E.L.; Hudson, E.A. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

150

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

SciTech Connect

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

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

1991-01-01

151

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

SciTech Connect

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

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

1991-12-31

152

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

SciTech Connect

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

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

1996-12-01

153

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

154

Elemental analysis of waste glass by x-ray fluorescence spectrometry  

SciTech Connect

An X-ray fluorescence (XRF) technique is reported which shows promise for the elemental analysis of low-level mixed waste glasses. This technique can be used for both quantitative laboratory analysis and process control. The glass-forming melts are cast into graphite molds and resulting disks are annealed and polished. The disk is then analyzed with a wavelength dispersive X-ray fluorescence spectrometer and the elemental intensities are converted into concentration with a fundamental parameters routine without the use of matrix-matched standards. Precision of elemental determinations are all better than one percent relative standard deviation. The XRF analysis has been compared with a reference method utilizing conventional wet chemical dissolution techniques followed by atomic spectroscopic determination. Results show that there is no significant difference between these two techniques, however, the XRF technique is much simpler and faster than the wet chemical methods.

Bickford, D.F.; Jurgensen, A.R. [Westinghouse Savannah River Co., Aiken, SC (United States); Resce, J.L.; Ragsdale, R.G.; Overcamp, T.J. [Clemson Univ., SC (United States)

1995-05-01

155

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

Microsoft Academic Search

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

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

2010-01-01

156

A high-resolution x-ray fluorescence spectrometer for near-edge absorption studies  

SciTech Connect

A high-resolution fluorescence spectrometer using a Johann geometry in a backscattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high-resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near-edge absorption spectrum of dysprosium nitrate.

Stojanoff, V.; Haemaelaeinen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G. (NSLS, Brookhaven National Laboratory, Upton, New York 11973 (United States))

1992-01-01

157

A High Resolution X-ray fluorescence spectrometer for near edge absorption studies  

SciTech Connect

A high-resolution fluorescence spectrometer using a Johann geometry in a backscattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high-resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near-edge absorption spectrum of dysprosium nitrate.

Stojanoff,V.; Hamalainen, K.; P Siddons, D.; B Hastings, J.; E Berman, L.; Cramer, S.; Smith, G.

1992-01-01

158

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

159

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

160

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

161

In vivo X-ray fluorescence of lead in bone: review and current issues.  

PubMed Central

Bone lead measurements can assess long-term lead dosimetry because the residence time of lead in bone is long. Bone lead measurements thus complement blood and plasma lead measurements, which reflect more short-term exposure. Although the noninvasive, in vivo measurement of lead in bone by X-ray fluorescence (XRF) has been under development since the 1970s, its use is still largely confined to research institutions. There are three principal methods used that vary both in the how lead X-rays are fluoresced and in which lead X-rays are fluoresced. Several groups have reported the independent development of in vivo measurement systems, the majority adopting the 109Cd K XRF method because of its advantages: a robust measurement, a lower detection limit (compared to 57Co K XRF), and a lower effective (radiation) dose (compared to L XRF) when calculated according to the most recent guidelines. These advantages, and the subsequent widespread adoption of the 109Cd method, are primarily consequences of the physics principles of the technique. This paper presents an explanation of the principles of XRF, a description of the practical measurement systems, a review of the human bone lead studies performed to date; and a discussion of some issues surrounding future application of the methods. Images p172-a PMID:8033846

Todd, A C; Chettle, D R

1994-01-01

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

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 ...

164

Geochemical analysis of marine sediments using fused glass disc by X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

A method was developed for content determination of Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard (for the trace elements). The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% ( n=12).

Xia, Ning; Zhang, Qin; Yao, De; Li, Guohui

2008-11-01

165

Downsizing of Johansson spectrometer for X-ray fluorescence trace analysis with brilliant undulator source  

NASA Astrophysics Data System (ADS)

The downsizing of a Johansson-type X-ray fluorescence (XRF) spectrometer has been examined as a way of enhancing detection efficiency with a tolerable loss of energy resolution. A compact spectrometer equipped with a Ge(2 2 0) analyzing crystal with a Rowland radius of 120 mm has been tested with a highly brilliant helical undulator source at BL40XU, SPring-8. The energy resolution obtained for cobalt K? 1 (6930.32 eV) was 8.8 eV, which is 10-20 times better than that obtained using a Si(Li) detector, and effectively improved the signal-to-background ratio for XRF spectra. The combination of the present spectrometer and a third generation synchrotron source could provide new opportunities for trace analytical applications, which have been difficult so far by conventional synchrotron XRF experiments based on a Si(Li) detector system. The detection limit obtained for solid bulk samples has reached a level of several tens of ppb.

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

2001-07-01

166

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

PubMed

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

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

2012-07-01

167

Characterization of buried thin films with resonant soft x-ray fluorescence  

SciTech Connect

The geometric and electronic structure of a buried monolayer of boron nitride (BN) has been probed using resonant soft x-ray fluorescence (SXF). By using the strong {pi}* resonance feature in the resonant fluorescence spectrum near the {ital B} (1{ital s}) threshold, we were able to detect the BN thin film and examine changes in its electronic structure when the monolayer is placed between different materials. Our results demonstrate the capability of the resonant SXF technique for probing the element-specific electronic structure of a buried thin film nondestructively. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Carlisle, J.A.; Terminello, L.J.; Hudson, E.A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Perera, R.C.C.; Underwood, J.H. [Lawrence Berkeley Laboratory, Berkeley, California 74720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 74720 (United States); Callcott, T.A.; Jia, J.J. [University of Tennessee, Knoxville, Tennessee 37996 (United States)] [University of Tennessee, Knoxville, Tennessee 37996 (United States); Ederer, D.L. [Tulane University, New Orleans, Louisiana 70118 (United States)] [Tulane University, New Orleans, Louisiana 70118 (United States); Himpsel, F.J. [IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States)] [IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Samant, M.G. [IBM Research Division, Almaden Research Center, San Jose, California 95120 (United States)] [IBM Research Division, Almaden Research Center, San Jose, California 95120 (United States)

1995-07-03

168

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

169

Optimization of in vivo X-ray fluorescence analysis methods for bone lead by simulation with the Monte Carlo code CEARXRF  

Microsoft Academic Search

In the design of X-ray fluorescence (XRF) systems for in vivo measurements of lead in human bone, the most important considerations are the minimum detectable concentration (MDC), and accuracy and precision. Possible design optimizations can be investigated much more easily and economically by Monte Carlo simulation than by experiment. The specific purpose Monte Carlo code CEARXRF has been used in

Q. Ao; S. H. Lee; R. P. Gardner

1997-01-01

170

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

171

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

172

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...

173

A new fundamental parameter based calibration procedure for micro X-ray fluorescence spectrometers  

NASA Astrophysics Data System (ADS)

Fundamental parameter based quantification of X-ray fluorescence (XRF) measurement data requires an accurate knowledge of the spectrometer parameters, including the spectral distribution of the excitation radiation. In case of micro-XRF where a polycapillary optic is utilized in the excitation channel this distribution is changed due to the transmission properties of the lens. A new calibration procedure, based on fluorescence data of thin standard samples, was developed to determine the excitation spectrum, i.e., the product of the X-ray tube spectrum and the transmission of the used X-ray optic of a micro-XRF setup. The calibration result was validated by the quantitative analyses of certified multi-element reference standards and shows uncertainties in the order of 2% for main components, 10% for minor elements and 25% for trace elements. The influence of secondary order effects like Coster-Kronig transitions and cascade effects is analyzed and the accuracy of fundamental parameters in common databases is discussed.

Wolff, Timo; Malzer, Wolfgang; Mantouvalou, Ioanna; Hahn, Oliver; Kanngießer, Birgit

2011-02-01

174

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

175

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

176

Scanning protein analysis of electrofocusing gels using X-ray fluorescence.  

PubMed

Recently, "metallomics," in addition to genomics and proteomics, has become a focus as a novel approach to identify sensitive fluctuations in homeostasis that accompany metabolic processes, such as stress responses, differentiation, and proliferation. Cellular elements and associated protein behavior provide important clues for understanding cellular and disease mechanism(s). It is important to develop a system for measuring the native status of the protein. In this study, we developed an original freeze-dried electrofocusing native gel over polyimide film (native-gel film) for scanning protein analysis using synchrotron radiation excited X-ray fluorescence (SPAX). To our knowledge, this is the first report detailing the successful mapping of metal-associated proteins of electrofocusing gels using X-ray fluorescence. SPAX can provide detection sensitivity equivalent to that of LA-ICP-MS. In addition to this increased sensitivity, SPAX has the potential to be combined with other X-ray spectroscopies. Our system is useful for further applications in proteomics investigating cellular element-associated protein behaviors and disease mechanisms. PMID:23576194

Matsuyama, Satoshi; Matsunaga, Akihiro; Sakamoto, Shinichi; Iida, Yutaka; Suzuki, Yoshinari; Ishizaka, Yukihito; Yamauchi, Kazuto; Ishikawa, Tetsuya; Shimura, Mari

2013-05-01

177

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

178

Advanced gated x-ray imagers for experiments at the National Ignition Facility  

Microsoft Academic Search

X-ray imaging is integral to the measurement of the properties of hot plasmas. To this end, a suite of gated x-ray imagers have been developed for use in a wide range of experiments at the National Ignition Facility (NIF). These instruments are sensitive to x-rays over the range of 0.7-90keV and can acquire images at 20ps intervals for source intensities

S. Glenn; P. M. Bell; L. R. Benedetti; D. K. Bradley; J. Celeste; R. Heeter; C. Hagmann; J. Holder; N. Izumi; J. D. Kilkenny; J. Kimbrough; G. A. Kyrala; N. Simanovskaia; R. Tommasini

2011-01-01

179

by a High-Altitude Balloon-Borne Experiment for Hard X-ray Astronomy  

Microsoft Academic Search

We have modelled the hard X-ray background expected for a high-altitude balloon flight of the Energetic X-ray Telescope Experiment (EXITE2), an imaging phoswich detector\\/telescope for the 20-600 keV energy range. Photon and neutron-induced contributions to the background are considered. We describe the code and the results of a series of simulations with different shielding configurations. The simulated hard X-ray background

Kenneth S. K. Lum; Joseph J. Mohr; Didier Barret; Jonathan E. Grindlay; Raj P. Manandhar

180

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

181

Ultrasoft (C,N,O) x-ray fluorescence detection: Proportional counters, focusing multilayer mirrors, and scattered light systematics  

SciTech Connect

Ultrasoft x-ray detection is discussed as applied to the fluorescence yield near edge spectroscopy (FYNES) technique. We describe a progression of improved ultra-high vacuum compatible soft x-ray proportional counters for FYNES measurements. The importance of energy dispersive detection is discussed and examples shown. Scattered light background problems are quantified and compared for several real samples. Finally, focusing multilayer mirror collection is introduced for reducing scattered light background and improved elemental differentiation in the fluorescence signal.

Fischer, D. A.; Colbert, J.; Gland, J. L.

1989-07-01

182

Transmission-corrected x-ray fluorescence analysis of uranium and plutonium solutions using a dual transmission source  

Microsoft Academic Search

The energy-dispersive x-ray fluorescence analysis (XRFA) technique has been implemented at several spent nuclear fuel reprocessing facilities for nondestructive measurements of uranium and\\/or plutonium concentrations in process streams and product storage tanks. An important factor in these quantitative measurements is the absorption of the fluoresced x-rays by the solution matrix, which must be taken into account to accurately quantify the

W. D. Ruhter; D. C. Camp

1987-01-01

183

Region of interest reconstruction in 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. It has long been believed that for each slice, the acquired measurement lines must span the entire object at every projection view over 180 degrees to avoid reconstructing images with so-called truncation artifacts. However, recent developments in tomographic reconstruction theory have overturned those long-held beliefs about minimum-data requirements and shown that it is possible to obtain exact reconstruction of ROIs from truncated projections. In this work, we show how to exploit these developments to allow for region of interest imaging in XFCT.

La Rivière, Patrick J.; Vargas, Phillip; Xia, Dan; Pan, Xiaochuan

2008-08-01

184

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

185

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

186

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

NASA Astrophysics Data System (ADS)

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 ?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 ?m.

Hirai, Yasuharu; Yoneyama, Akio; Hisada, Akiko; Uchida, Kenko

2007-01-01

187

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

188

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

189

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

190

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

SciTech Connect

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

Worley, Christopher G [Los Alamos National Laboratory

2009-01-01

191

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

192

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

193

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

PubMed

Soft X-ray cryo-microscopy/tomography of vitreous samples is becoming a valuable tool in structural cell biology. Within the 'water-window' wavelength region (2.34-4.37nm), 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

2012-02-01

194

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

195

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

196

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

197

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

198

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

199

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

200

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

201

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

202

Airborne Particulate Matter (PM) filter analysis and modeling by Total reflection X-Ray Fluorescence (TXRF) and X-Ray Standing Wave (XSW)  

PubMed Central

This work is presented as an improvement of a recently introduced method for airborne particulate matter (PM) filter analysis [1]. X-ray Standing Wave (XSW) and Total reflection X-Ray Fluorescence (TXRF) were performed with a new dedicated laboratory instrumentation. The main advantage of performing both XSW and TXRF, is the possibility to distinguish the nature of the sample: if it is a small droplet dry residue, a thin film like or a bulk sample; and to select the angle of total reflection to make TXRF measurements. Finally, the possibility to switch the X-ray source allows to measure with more accuracy lighter and heavier elements (with a a change in X-ray anode, for example from Mo to Cu). The aim of the present study is to lay the theoretical foundation of the new proposed method for airborne PM filters quantitative analysis improving the accuracy and efficiency of quantification by means of an external standard. The theoretical model presented and discussed demonstrated that airborne PM filters can be considered as thin layers. A set of reference samples is prepared in laboratory and used to obtain a calibration curve. Our results demonstrate that the proposed method for quantitative analysis of air PM filters is affordable and reliable without the necessity to digest filters to obtain quantitative chemical analysis, and that the use of XRW improve the accuracy of TXRF analysis. PMID:22284465

Borgese, L.; Salmistraro, M.; Gianoncelli, A; Zacco, A.; Lucchini, R.; Zimmerman, N.; Pisani, L.; Siviero, G.; Depero, L. E.; Bontempi, E.

2011-01-01

203

Advanced combined application of micro-X-ray diffraction/micro-X-ray fluorescence with conventional techniques for the identification of pictorial materials from Baroque Andalusia paintings.  

PubMed

The process of investigating paintings includes the identification of materials to solve technical and historical art questions, to aid in the deduction of the original appearance, and in the establishment of the chemical and physical conditions for adequate restoration and conservation. In particular, we have focused on the identification of several samples taken from six famous canvases painted by Pedro Atanasio Bocanegra, who created a very special collection depicting the life of San Ignacio, which is located in the church of San Justo y Pastor of Granada, Spain. The characterization of the inorganic and organic compounds of the textiles, preparation layers, and pictorial layers have been carried out using an XRD diffractometer, SEM observations, EDX spectrometry, FT-IR spectrometry (both in reflection and transmission mode), pyrolysis/gas chromatography/mass spectrometry and synchrotron-based micro-X-ray techniques. In this work, the advantages over conventional X-ray diffraction of using combined synchrotron-based micro-X-ray diffraction and micro-X-ray fluorescence in the identification of multi-layer paintings is demonstrated. PMID:19782194

Herrera, L K; Montalbani, S; Chiavari, G; Cotte, M; Solé, V A; Bueno, J; Duran, A; Justo, A; Perez-Rodriguez, J L

2009-11-15

204

X-ray fluorescence analysis of iron and manganese distribution in primary dopaminergic neurons.  

PubMed

Transition metals have been suggested to play a pivotal role in the pathogenesis of Parkinson's disease. X-ray microscopy combined with a cryogenic setup is a powerful method for elemental imaging in low concentrations and high resolution in intact cells, eliminating the need for fixation and sectioning of the specimen. Here, we performed an elemental distribution analysis in cultured primary midbrain neurons with a step size in the order of 300 nm and ~ 0.1 ppm sensitivity under cryo conditions by using X-ray fluorescence microscopy. We report the elemental mappings on the subcellular level in primary mouse dopaminergic (DAergic) and non-DAergic neurons after treatment with transition metals. Application of Fe(2+) resulted in largely extracellular accumulation of iron without preference for the neuronal transmitter subtype. A quantification of different Fe oxidation states was performed using X-ray absorption near edge structure analysis. After treatment with Mn(2+) , a cytoplasmic/paranuclear localization of Mn was observed preferentially in DAergic neurons, while no prominent signal was detectable after Mn(3+) treatment. Immunocytochemical analysis correlated the preferential Mn uptake to increased expression of voltage-gated calcium channels in DAergic neurons. We discuss the implications of this differential elemental distribution for the selective vulnerability of DAergic neurons and Parkinson's disease pathogenesis. PMID:23106162

Du?i?, Tanja; Barski, Elisabeth; Salome, Murielle; Koch, Jan C; Bähr, Mathias; Lingor, Paul

2013-01-01

205

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

206

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

207

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

PubMed

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

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

2013-11-01

208

X-ray fluorescence analysis of iron and manganese distribution in primary dopaminergic neurons  

PubMed Central

Transition metals have been suggested to play a pivotal role in the pathogenesis of Parkinson's disease. X-ray microscopy combined with a cryogenic setup is a powerful method for elemental imaging in low concentrations and high resolution in intact cells, eliminating the need for fixation and sectioning of the specimen. Here, we performed an elemental distribution analysis in cultured primary midbrain neurons with a step size in the order of 300 nm and ? 0.1 ppm sensitivity under cryo conditions by using X-ray fluorescence microscopy. We report the elemental mappings on the subcellular level in primary mouse dopaminergic (DAergic) and non-DAergic neurons after treatment with transition metals. Application of Fe2+ resulted in largely extracellular accumulation of iron without preference for the neuronal transmitter subtype. A quantification of different Fe oxidation states was performed using X-ray absorption near edge structure analysis. After treatment with Mn2+, a cytoplasmic/paranuclear localization of Mn was observed preferentially in DAergic neurons, while no prominent signal was detectable after Mn3+ treatment. Immunocytochemical analysis correlated the preferential Mn uptake to increased expression of voltage-gated calcium channels in DAergic neurons. We discuss the implications of this differential elemental distribution for the selective vulnerability of DAergic neurons and Parkinson's disease pathogenesis. PMID:23106162

Du?i?, Tanja; Barski, Elisabeth; Salome, Murielle; Koch, Jan C; Bähr, Mathias; Lingor, Paul

2013-01-01

209

Development of Ta-based Superconducting Tunnel Junction X-ray Detectors for Fluorescence XAS  

SciTech Connect

We are developing superconducting tunnel junction (STJ) soft X-ray detectors for chemical analysis of dilute samples by fluorescence-detected X-ray absorption spectroscopy (XAS). Our 36-pixel Nb-based STJ spectrometer covers a solid angle {Omega}/4{pi} {approx} 10{sup -3}, offers an energy resolution of {approx}10-20 eV FWHM for energies up to {approx}1 keV, and can be operated at total count rates of {approx}10{sup 6} counts/s. For increased quantum efficiency and cleaner response function, we have now started the development of Ta-based STJ detector arrays. Initial devices modeled after our Nb-based STJs have an energy resolution below 10 eV FWHM for X-ray energies below 1 keV, and pulse rise time discrimination can be used to improve their response function for energies up to several keV. We discuss the performance of the Ta-STJs and outline steps towards the next-generation of large STJ detector arrays with higher sensitivity.

Friedrich, S; Drury, O; Hall, J; Cantor, R

2009-09-23

210

Development of Ta-based Superconducting Tunnel Junction X-ray Detectors for Fluorescence XAS  

SciTech Connect

We are developing superconducting tunnel junction (STJ) soft X-ray detectors for chemical analysis of dilute samples by fluorescence-detected X-ray absorption spectroscopy (XAS). Our 36-pixel Nb-based STJ spectrometer covers a solid angle {Omega}/4{pi}{approx_equal}10{sup -3}, offers an energy resolution of {approx}10-20 eV FWHM for energies up to {approx}1 keV, and can be operated at total count rates of {approx}10{sup 6} counts/s. For increased quantum efficiency and cleaner response function, we have now started the development of Ta-based STJ detector arrays. Initial devices modeled after our Nb-based STJs have an energy resolution below 10 eV FWHM for X-ray energies below 1 keV, and pulse rise time discrimination can be used to improve their response function for energies up to several keV. We discuss the performance of the Ta-STJs and outline steps towards the next-generation of large STJ detector arrays with higher sensitivity.

Friedrich, Stephan; Drury, Owen B. [Lawrence Livermore National Lab, Advanced Detector Group, 7000 East Ave., L-188, Livermore, CA 94550 (United States); Hall, John; Cantor, Robin [STAR Cryoelectronics, 25-A Bisbee Court, Santa Fe, NM 87508 (United States)

2010-06-23

211

Proton-induces and x-ray induced fluorescence analysis of scoliotic tissue  

SciTech Connect

Adolescent idiopathic scoliosis is characterized by a curvature or assymetry of the spine which may become progressively more severe, with clinical symptoms appearing just prior to, or during, puberty. The incidence for scoliosis in the age group from 12 to 14 years of age has been reported as high as 8 to 10%, with more than 80% of the cases occurring in females. Although pathologic changes exist in muscles from both sides of the spinal curvature, and no statistically significant side differences have been reported, morphologic changes suggest that the concanve side is the most affected. This paper reports our preliminary data on the elemental composition of individual muscle fibers derived from convex, concave and gluteal scoliotic muscle, and erythrocytes from scoliotic and normal patients, analyzed by proton induced x-ray emission (PIXE) and x-ray fluorescence spectroscopy (XRF). A new type of specimen holder was designed for this study which offers low x-ray background, minimal absorption and maintenance of a moist environment around the specimen.

Panessa-Warren, B J; Kraner, H W; Jones, K W; Weiss, L S

1980-02-01

212

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

213

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

214

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

215

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

216

Analysis of obsidian artifacts in Southern Meso-America using x-ray fluorescence  

SciTech Connect

The analysis of obsidian artifacts using X-ray fluorescence (XRF) spectrometry has been an important tool for archaeologists for {approximately}25 yr. However, as methods and instrumentation have improved, more reliable information regarding exchange and routes of exchange has been obtained. In southern Meso-America, obsidian analyses have demonstrated changes in the obsidian geologic sources used by prehistoric peoples through time. These changes in sources of obsidian have been used to describe possible changes of prehistoric trade routes. The methods and results of analysis are described in this paper.

Nelson, F.W. [Brigham Young Univ., Provo, UT (United States)

1996-12-31

217

First Total Reflection X-Ray Fluorescence round-robin test of water samples: Preliminary results  

NASA Astrophysics Data System (ADS)

Total Reflection X-Ray Fluorescence (TXRF) is a mature technique to evaluate quantitatively the elemental composition of liquid samples deposited on clean and well polished reflectors. In this paper the results of the first worldwide TXRF round-robin test of water samples, involving 18 laboratories in 10 countries are presented and discussed. The test was performed within the framework of the VAMAS project, interlaboratory comparison of TXRF spectroscopy for environmental analysis, whose aim is to develop guidelines and a standard methodology for biological and environmental analysis by means of the TXRF analytical technique.

Borgese, Laura; Bilo, Fabjola; Tsuji, Kouichi; Fernández-Ruiz, Ramón; Margui, Eva; Streli, Christina; Pepponi, Giancarlo; Stosnach, Hagen; Yamada, Takashi; Vandenabeele, Peter; Maina, David M.; Gatari, Michael; Shepherd, Keith D.; Towett, Erick K.; Bennun, Leonardo; Custo, Graciela; Vasquez, Cristina; Depero, Laura E.

2014-11-01

218

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

219

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

220

Waste reduction and process improvements in the analysis of plutonium by x-ray fluorescence  

SciTech Connect

Significant modifications were made to a sample preparation process for quantifying gallium in plutonium metal by wavelength dispersive X-ray fluorescence. These changes were made to minimize waste and improve process safety and efficiency. Sample sizes were reduced, cheaper sample preparation acids were used, and safety improvements were implemented. Using this modified process, results from analyzing a batch oftest samples indicated that relative precision and accuracy were {approx}0.2% and {approx}0.1% respectively, which is comparable to that obtained using the older, established sample preparation method.

Worley, Christopher G [Los Alamos National Laboratory; Sodweberg, Constance B [Los Alamos National Laboratory; Townsend, Lisa E [Los Alamos National Laboratory

2009-01-01

221

An x-ray fluorescence study of lake sediments from ancient Turkey using synchrotron radiation.  

SciTech Connect

Sediments from relic Lake Golbasi were analyzed by X-ray fluorescence with synchrotrons radiation to determine changes in element concentrations over time with selected elements serving as proxies for environmental change. Increases in Ca and Sr suggest soil formation during a dry period, from ca. 4500 BC to ca. 200 AD at which point K, Rb, Zr, Ti, and Y increase, indicating the return of a wet environment. Soil erosion, represented by Cr and Ni, increases ca. 7000 BC, probably as a consequence of environmental change, prior to suggested exploitation of natural resources by the newly urbanized society of the third millennium BC.

Alatas, A.; Alp, E. E.; Friedman, E. S.; Jennings, G.; Johnson, C. E.; Lai, B.; Mini, S. M.; Sato, Y.; Wilkinson, T. J.; Yener, K. A.

1999-03-10

222

A high resolution x-ray fluorescence spectrometer for near edge absorption studies  

SciTech Connect

A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

1991-12-31

223

A high resolution x-ray fluorescence spectrometer for near edge absorption studies  

SciTech Connect

A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

1991-01-01

224

Analyses of lake sediments from Itaipú dam using x-ray fluorescence  

NASA Astrophysics Data System (ADS)

The objective of this study was to use principal component analysis (PCA), with data from Energy Dispersive X-Ray Fluorescence (EDXRF) of sediment samples from Itaipú artificial beaches, to find correlations between metal concentrations present in the sediments and physical-chemical properties. Samples were collected at nine points at Itaipu dam lake dam from 80 cm depth of water column, dried at room temperature and grinded in a mortar to obtain a particle size lower than 70 ?m. The samples with higher concentration of organic matter and metal ions have correlation with the smaller sample size, i.e., clay.

dos Santos, Felipe Rodrigues; Novacoski, Ezequiel J.; Melquiades, Fábio L.

2013-05-01

225

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

226

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

227

Experiments with diamond-turned metal X-ray mirrors  

NASA Technical Reports Server (NTRS)

It is noted that the primary advantages of diamond turning technology for the fabrication of X-ray telescope mirrors is in the smoothness of the finished surface and the control of the position of the cutter afforded by the precision slides and computer-assisted positioners which form the surface. The paper summarizes the Caltech work in attempting to make Wolter Type I telescope mirrors using the diamond turning facilities at the Oak Ridge Y-12 laboratory. Attention is given to such factors as the use of aluminum with copper plating and electroless nickel coating. It is found that although the diamond turning capability of the Y-12 lab is capable of making good X-ray mirror contours, there are problems in the process which have limited the accuracy achieved by this technique.

Garmire, G. P.

1979-01-01

228

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

229

The X-ray telescope of the CAST experiment  

Microsoft Academic Search

The CERN Axion Solar Telescope (CAST) searches for solar axions employing a 9 tesla superconducting dipole magnet equipped with 3 independent detection systems for X-rays from axion-photon conversions inside the 10 m long magnetic field. Results of the first 6 months of data taking in 2003 imply a 95% CL upper limit on the axion-photon coupling constant of gagamma <

R. Kotthaus; H. Braeuninger; P. Friedrich; R. Hartmann; D. Kang; M. Kuster; G. Lutz; L. Strueder

2005-01-01

230

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

231

[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

232

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

233

Quantitatively imaging chromosomes by correlated cryo-fluorescence and soft x-ray tomographies.  

PubMed

Soft x-ray tomography (SXT) is increasingly being recognized as a valuable method for visualizing and quantifying the ultrastructure of cryopreserved cells. Here, we describe the combination of SXT with cryogenic confocal fluorescence tomography (CFT). This correlative approach allows the incorporation of molecular localization data, with isotropic precision, into high-resolution three-dimensional (3-D) SXT reconstructions of the cell. CFT data are acquired first using a cryogenically adapted confocal light microscope in which the specimen is coupled to a high numerical aperture objective lens by an immersion fluid. The specimen is then cryo-transferred to a soft x-ray microscope (SXM) for SXT data acquisition. Fiducial markers visible in both types of data act as common landmarks, enabling accurate coalignment of the two complementary tomographic reconstructions. We used this method to identify the inactive X chromosome (Xi) in female v-abl transformed thymic lymphoma cells by localizing enhanced green fluorescent protein-labeled macroH2A with CFT. The molecular localization data were used to guide segmentation of Xi in the SXT reconstructions, allowing characterization of the Xi topological arrangement in near-native state cells. Xi was seen to adopt a number of different topologies with no particular arrangement being dominant. PMID:25418180

Smith, Elizabeth A; McDermott, Gerry; Do, Myan; Leung, Karen; Panning, Barbara; Le Gros, Mark A; Larabell, Carolyn A

2014-10-21

234

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

235

X-ray fluorescence and absorption analysis of krypton in irradiated nuclear fuel  

NASA Astrophysics Data System (ADS)

The analysis of krypton in irradiated uranium dioxide fuel has been successfully achieved by X-ray fluorescence and X-ray absorption. The present study focuses on the analytical challenge of sample and sub-sample production to perform the analysis with the restricted conditions dictated by the radioprotection regulations. It deals also with all potential interferences that could affect the quality of the measurement in fluorescence as well as in absorption mode. The impacts of all dissolved gases in the fuel matrix are accounted for the analytical result quantification. The krypton atomic environment is ruled by the presence of xenon. Other gases such as residual argon and traces of helium or hydrogen are negligible. The results are given in term of density for krypton (?3 nm-3) and xenon (?20 nm-3). The presence of dissolved, interstitial and nano-phases are discussed together with other analytical techniques that could be applied to gain information on fission gas behaviour in nuclear fuels.

Degueldre, Claude; Mieszczynski, Cyprian; Borca, Camelia; Grolimund, Daniel; Martin, Matthias; Bertsch, Johannes

2014-10-01

236

Determination of ultratrace concentrations of uranium and thorium in natural waters by x-ray fluorescence  

SciTech Connect

An x-ray fluorescence method for the simultaneous determination of uranium and thorium at the less than 1 ppM level in natural waters is described. Uranium and thorium are coprecipitated with an internal standard, yttrium, and incorporated into an iron-aluminum hydroxide carrier. The hydroxide precipitate is filtered, and the filter disk is analyzed by the energy-dispersive x-ray fluorescence technique. Matrix interferences caused by the presence of unpredictable anions and cations are compensated for by the internal standard. The U/Y and Th/Y ratios are linear over the 5- to 100-..mu..g range of interest, and the detection limit of each element on the filter disk is 2 ..mu..g (3 sigma). Relative standard deviation was 17% at the 15-..mu..g and 4% at the 100-..mu..g level for thorium and 11% at the 11-..mu..g and 2% at the 100-..mu..g level for uranium. Analysis of spiked solutions showed a recovery of 19.6 +- 0.3 ..mu..g for uranium and 19.8 +- 0.3 ..mu..g for thorium at the 20-..mu..g level, and the normal lower reporting limit is 5 ..mu..g. Fifty disks can be routinely measured during a normal working day.

Stewart, J.H. Jr.; Brooksbank, R.D.

1981-01-01

237

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

238

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

239

Promising X-ray fluorescent tests for superconducting tunnel junction detector  

SciTech Connect

Scientists in the Physical Biosciences Division of the Ernest Orlando Berkeley National Laboratory (Berkeley Lab) studying transition metals in proteins with fluorescence-detected L-edge absorption spectroscopy have found the measurements to be extremely challenging. The difficulty is that the metal centers are present in very dilute concentrations so that their weak fluorescence is often obscured by strong background signals from carbon and oxygen. To solve this problem, the Berkeley group has been working with researchers from the Advanced Detector Group at the Lawrence Livermore National Laboratory on an energy-dispersive superconducting tunnel junction x-ray detector. These devices in principle have the energy resolution needed to reveal the metal signal. The most recent results with the latest version of the detector on Beamline 4.0.1-2 at the Advanced Light Source (ALS) illustrate the promise of the cryogenic detector strategy not only for this application but also for spectroscopy of other types of dilute samples.

Friedrich, Stephan; Robinson, Art

2001-01-11

240

Development of a hard X-ray delay line for X-ray photon correlation spectroscopy and jitter-free pump–probe experiments at X-ray free-electron laser sources  

PubMed Central

A hard X-ray delay line capable of splitting and delaying single X-ray pulses has been developed with the aim of performing X-ray photon correlation spectroscopy (XPCS) and X-ray pump–probe experiments at hard X-ray free-electron laser sources. The performance of the device was tested with 8.39?keV synchrotron radiation. Time delays up to 2.95?ns have been demonstrated. The feasibility of the device for performing XPCS studies was tested by recording static speckle patterns. The achieved speckle contrast of 56% indicates the possibility of performing ultra-fast XPCS studies with the delay line. PMID:21525658

Roseker, Wojciech; Franz, Hermann; Schulte-Schrepping, Horst; Ehnes, Anita; Leupold, Olaf; Zontone, Federico; Lee, Sooheyong; Robert, Aymeric; Grübel, Gerhard

2011-01-01

241

Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera  

NASA Astrophysics Data System (ADS)

Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by “drop on demand” technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation.

Fittschen, Ursula Elisabeth Adriane; Menzel, Magnus; Scharf, Oliver; Radtke, Martin; Reinholz, Uwe; Buzanich, Günther; Lopez, Velma M.; McIntosh, Kathryn; Streli, Christina; Havrilla, George Joseph

2014-09-01

242

An X-ray spectroscopy system and its application to the laser-Compton scattering experiments  

Microsoft Academic Search

One of the main challenges for the laser-Compton scattering (LCS) experiments with the oblique configuration at the Linac of SINAP is the low signal to noise (S\\/N) ratio due to the low intensity of LCS signals. X-ray spectroscopy system mainly consisting of an X-ray Si(Li) detector, electronics, and LabVIEW-based data acquisition has been developed for the low S\\/N ratio experiments.

W. Luo; W. Xu; Q. Y. Pan; G. T. Fan; G. W. Fan; Y. J. Li; B. J. Xu; Y. Xu; Z. Yan; L. F. Yang

2010-01-01

243

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

244

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

245

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

246

A new multichannel soft x-ray framing camera for fusion experiments  

SciTech Connect

Two dimensional, time resolved x-ray imaging is a principal technique used to study hot plasmas produced in laser heated targets. It can be used to study laser energy deposition within the irradiation spot, the spatial and temporal dependence of laser to x-ray conversion efficiency, electron transport and density profiles, mass ablation rates as well as x-ray driven implosions in inertial confinement fusion experiments. We have successfully developed a new soft x-ray framing camera which will allow us to record two-dimensional images at different times almost simultaneously. It is a broad band diagnostic (100 eV[le] [Delta]h[radical] [le] 400 eV) having three channels which can obtain x-ray images at four different times from laser driven targets. Its current configuration includes one 500 eV, one 1.0 keV and one [approximately]2.5 key channels. The two low energy channels resulted from pairing transmission filters to grazing x-ray mirrors. Other channel options can be implemented easily to measure other x-ray energies. Four different striplines coated on a microchannel plate are gated at different times. Each strip records three different images taken nearly simultaneously, one image per channel. The result is twelve x-ray images on film, four images per channel taken at four different times, with a nominal resolution of approximately 100 ps per image. The diagnostic's spatial resolution is approximately 10 [mu]m. We have already fielded this new instrument during x-ray conversion experiments, using both low and high Z targets driven by 1ns-2ns, flat top'' laser pulses. We will show the details of the instrument design and sample results from conversion experiments.

Ze, F.; Kauffman, R.L.; Kilkenny, J.D.; Wielwald, J.; Bell, P.M.; Hanks, R.; Stewart, J.; Dean, D.; Bower, J.; Wallace, R.

1992-03-20

247

A new multichannel soft x ray framing camera for fusion experiments  

NASA Astrophysics Data System (ADS)

Two dimensional, time resolved x-ray imaging is a principal technique used to study hot plasmas produced in laser heated targets. It can be used to study laser energy deposition within the irradiation spot, the spatial and temporal dependence of laser to x-ray conversion efficiency, electron transport and density profiles, mass ablation rates as well as x-ray driven implosions in inertial confinement fusion experiments. A new soft x-ray framing camera which will allow us to record two-dimensional images at different times almost simultaneously was successfully developed. It is a broad band diagnostic (100 eV less than or equal to delta(h(radical)) less than or equal to 400 eV) having three channels which can obtain x-ray images at four different times from laser driven targets. Its current configuration includes one 500 eV, one 1.0 keV, and one approximately 2.5 keV channels. The two low energy channels resulted from pairing transmission filters to grazing x-ray mirrors. Other channel options can be implemented easily to measure other x-ray energies. Four different striplines coated on a microchannel plate are gated at different times. Each strip records three different images taken nearly simultaneously, one image per channel. The result is twelve x-ray images on film, four images per channel taken at four different times, with a nominal resolution of approximately 100 ps per image. The diagnostics' spatial resolution is approximately 10 microns. This new instrument was already fielded during x-ray conversion experiments, using both low and high Z targets driven by 1ns-2ns, 'flat top' laser pulses. The details of the instrument design and sample results from conversion experiments are shown.

Ze, F.; Kauffman, R. L.; Kilkenny, J. D.; Wielwald, J.; Bell, P. M.; Hanks, R.; Stewart, J.; Dean, D.; Bower, J.; Wallace, R.

1992-03-01

248

A new multichannel soft x-ray framing camera for fusion experiments  

SciTech Connect

Two dimensional, time resolved x-ray imaging is a principal technique used to study hot plasmas produced in laser heated targets. It can be used to study laser energy deposition within the irradiation spot, the spatial and temporal dependence of laser to x-ray conversion efficiency, electron transport and density profiles, mass ablation rates as well as x-ray driven implosions in inertial confinement fusion experiments. We have successfully developed a new soft x-ray framing camera which will allow us to record two-dimensional images at different times almost simultaneously. It is a broad band diagnostic (100 eV{le} {Delta}h{radical} {le} 400 eV) having three channels which can obtain x-ray images at four different times from laser driven targets. Its current configuration includes one 500 eV, one 1.0 keV and one {approximately}2.5 key channels. The two low energy channels resulted from pairing transmission filters to grazing x-ray mirrors. Other channel options can be implemented easily to measure other x-ray energies. Four different striplines coated on a microchannel plate are gated at different times. Each strip records three different images taken nearly simultaneously, one image per channel. The result is twelve x-ray images on film, four images per channel taken at four different times, with a nominal resolution of approximately 100 ps per image. The diagnostic`s spatial resolution is approximately 10 {mu}m. We have already fielded this new instrument during x-ray conversion experiments, using both low and high Z targets driven by 1ns-2ns, ``flat top`` laser pulses. We will show the details of the instrument design and sample results from conversion experiments.

Ze, F.; Kauffman, R.L.; Kilkenny, J.D.; Wielwald, J.; Bell, P.M.; Hanks, R.; Stewart, J.; Dean, D.; Bower, J.; Wallace, R.

1992-03-20

249

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

250

X-ray fluoresced high-Z (up to Z=82) K x rays produced by LiNbO{sub 3} and LiTaO{sub 3} pyroelectric crystal electron accelerators  

SciTech Connect

High-energy bremsstrahlung and K x rays were used to produce nearly background-free K x-ray spectra of up to 87 keV (Pb) via x-ray fluorescence. The fluorescing radiation was produced by electron accelerators, consisting of heated and cooled cylindrical LiTaO{sub 3} and LiNbO{sub 3} crystals at mTorr pressures. The process of gas amplification whereby the ambient gas pressure is optimized to maximize the electron energy was used to produce energetic electrons which when incident on a W/Bi target, gave rise to a radiation field consisting of high-energy bremsstrahlung as well as W and Bi K x rays. These photons were used to fluoresce Ta and Pb K x rays.

Brownridge, James D.; Shafroth, Stephen M. [Department of Physics, Applied Physics and Astronomy, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902-6000 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255 (United States)

2004-08-16

251

Spatially resolved synchrotron radiation induced X-ray fluorescence analyses of rare Rembrandt silverpoint drawings  

NASA Astrophysics Data System (ADS)

New analyses of a series of very rare silverpoint drawings that were executed by Rembrandt Harmensz. van Rijn (1606 1669) which are kept today in the Kupferstichkabinett (Museum of Prints and Drawings) of the State Museums of Berlin are reported here. Analysis of these drawings requires particular attention because the study has to be fully non-destructive and extremely sensitive. The metal alloy on the paper does not exceed some hundreds of ?g/cm2. Therefore, synchrotron radiation induced X-ray fluorescence (SR-XRF) is together with external micro-proton-induced X-ray emission the only well-suited method for the analyses of metalpoint drawings. In some primary work, about 25 German and Flemish metalpoint drawings were investigated using spatially resolved SR-XRF analysis at the BAMline at BESSY. This study enlarges the existing French German database of metalpoint drawings dating from the 15th and 16th centuries, as these Rembrandt drawings originate from the 17th century where this graphical technique was even rarer and already obsolete. It also illustrates how SR-XRF analysis can reinforce art historical assumptions on the dating of drawings and their connection.

Reiche, I.; Radtke, M.; Berger, A.; Görner, W.; Merchel, S.; Riesemeier, H.; Bevers, H.

2006-05-01

252

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

253

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

254

Imaging metals in proteins by combining electrophoresis with rapid x-ray fluorescence mapping.  

SciTech Connect

Growing evidence points toward a very dynamic role for metals in biology. This suggests that physiological circumstance may mandate metal ion redistribution among ligands. This work addresses a critical need for technology that detects, identifies, and measures the metal-containing components of complex biological matrixes. We describe a direct, user-friendly approach for identifying and quantifying metal?protein adducts in complex samples using native- or SDS-PAGE, blotting, and rapid synchrotron X-ray fluorescence mapping with micro-XANES (X-ray absorption near-edge structure) of entire blots. The identification and quantification of each metal bound to a protein spot has been demonstrated, and the technique has been applied in two exemplary cases. In the first, the speciation of the in vitro binding of exogenous chromium to blood serum proteins was influenced markedly by both the oxidation state of chromium exposed to the serum proteins and the treatment conditions, which is of relevance to the biochemistry of Cr dietary supplements. In the second case, in vivo changes in endogenous metal speciation were examined to probe the influence of oxygen depletion on iron speciation in Shewanella oneidensis.

Finney, L.; Chishti, Y.; Khare, T.; Giometti, C.; Levina, A.; Lay, P. A.; Vogt, S.; Univ. of Sydney; Northwestern Univ.

2010-01-01

255

Apollo 16 geochemical X-ray fluorescene experiment: Preliminary report  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

256

Application of conventional and microbeam synchrotron radiation x-ray fluorescence and absorption for the characterization of human nails.  

PubMed

The synchrotron radiation based spectroscopies X-ray fluorescence and X-ray absorption fine structure are used to detect illness-related changes in the elemental distribution and bonding environment of metals in human nails. The effective atomic number of a collection of nails is determined using two methods, the X-ray transmittance and the scattering method, and is found equal to 7.5 +/- 0.5. X-ray fluorescence maps of the elemental distributions, recorded with a lateral resolution of 5 microm, reveal that S, Ca and Zn are distributed homogeneously while Fe tends to cluster. In the Fe-rich clusters, which have a diameter in the range 15-30 microm, the Fe concentration is 10 times higher than in the matrix. The Zn K edge X-ray Absorption Fine Structure spectra reveal that Zn, in the nails from healthy donors and patients suffering from lung diseases, is four-fold coordinated with N and S and the Zn-N and Zn-S distances are equal to 2.03 A and 2.25 A, respectively. Finally the signature of various bonds in the C-, O- and N- K near edge X-ray absorption fine structure spectra is discussed. PMID:21133186

Katsikini, M; Mavromati, A; Pinakidou, F; Paloura, E C; Gioulekas, D; Loannides, D; Erko, A; Zizak, I

2010-09-01

257

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

NASA Astrophysics Data System (ADS)

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 °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 (O2, H2, H2O2, 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 (H2O2) in methanol solution from dihydrogen and dioxygen.

Centomo, P.; Meneghini, C.; Zecca, M.

2013-05-01

258

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

259

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

260

Local Clusters in a Distorted Rocksalt GeTe Crystal Found by X-ray Fluorescence Holography  

NASA Astrophysics Data System (ADS)

A Ge K? X-ray fluorescence holography (XFH) measurement was performed on a single-crystal GeTe film with a deformed rocksalt (rhombohedral) lattice, for which careful analyses and observations of the reconstructed atomic images were needed. The three-dimensional atomic images obtained around the central Ge atom were compared with the theoretical images obtained from a simulated hologram in the full sphere range and in the limited ? range (0 < ? < 74°), as in the experiment. It was found that reliable atomic images were realized only when neighboring atoms are located on the surface side of the central Ge atom. GeTe3 clusters were found by XFH, which cannot be easily detected by diffraction, and confirmed by ab initio molecular dynamics simulation.

Hosokawa, Shinya; Happo, Naohisa; Senba, Shinya; Ozaki, T?ru; Matsushita, Tomohiro; Koura, Akihide; Shimojo, Fuyuki; Hayashi, Kouichi

2014-12-01

261

Utilization of X-ray Phase Contrast Imaging in ICF and HEDP Experiments  

NASA Astrophysics Data System (ADS)

X-ray phase contrast imaging (XPCI) provides new diagnostic opportunities in inertial confinement fusion (ICF) and high-energy density physics (HEDP) experiments, including static characterization of cryogenic fuel layers in ICF capsules, and measurement of shock interfaces in low-Z high density plasmas. This novel technique relies on gradients in the phase of an object, rather than absorption, to provide image contrast. A wave propagation code has been developed to simulate the image formation process for synthesized objects in order to investigate the application of XPCI under various scenarios. Additionally, preliminary experimental results using a laboratory micro-focus x-ray source to image static objects, and a laser-produced x-ray point source to image HEDP plasma experiments will be presented. The required x-ray source and detection characteristics to optimize XPCI will be discussed, and numerical modeling results for various synthesized objects will be presented.

Montgomery, David S.

2004-11-01

262

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

263

X-ray cell tracking: from ex-vivo to in-vivo experiments  

NASA Astrophysics Data System (ADS)

The capacity to track cells (cell tracking) using x-rays on ex-vivo specimens of both malignant and non-malignant cell lines on small animals has been demonstrated recently. Gold nanoparticles have been used as a cellular contrast agent to render cells visible in x-ray microCT acquisitions. The limits of the technique proposed are basically driven by the imaging system used. Single cell resolution can be achieved using synchrotron radiation in-vitro or ex-vivo samples. Micro-focus x-ray tubes can be used to obtain high resolution cell tracking but with some limitations. However, the translation from ex-vivo to in-vivo experiments is not straightforward. The dose restrictions required for in-vivo longitudinal experiments set severe limitations on the technique. Here we present a detailed investigation showing a significant reduction of x-ray dose for the tracking of brain tumour cells. Monte Carlo simulations have been performed considering different spatial resolutions, photon fluence, number of projections, lesion dimension and cell contrast dilution. The findings are compared with real samples imaged using the same parameters. A pioneering in-vivo experiment conducted at the SYRMEP beamline (Elettra, Basovizza, Italy) is presented here as proof of principle of in-vivo longitudinal x-ray cell tracking experiments on small animals at low x-ray doses.

Astolfo, A.; Schültke, E.; Menk, R.-H.; Hall, C.; Juurlink, B.; Arfelli, F.

2013-06-01

264

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

265

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

266

[Analysis of 14 elements for Jinhua bergamot by X-ray fluorescence spectrometry and elemental analyser].  

PubMed

The content of the elements C, H, O and N in Jinhua bergamot was analysed by using Vario III elemental analyser, the bergamot sample was scanned by using X-ray fluorescence spectrometer with PW2400 wavelength dispersion, and the content of the elements Mg, Al, P, S, Cl, K, Ca, Mn, Fe and Sr was analysed by using IQ+ analytical method. It turned out that the result is more ideal if the content of the elements C, H, O and N is processed as fix phase, and the analytical result is more ideal if, to prevent the sample skin from coming off, the sample is wrapped with mylar film with the film coefficient adjusted. PMID:22497170

Wang, Zhi-gang; Yu, Hong-mei

2012-01-01

267

Performance of a Borehole X-ray Fluorescence Spectrometer for Planetary Exploration  

NASA Technical Reports Server (NTRS)

We have designed and constructed a borehole X-ray Fluorescence Spectrometer (XRFS) as part of the Mars Subsurface Access program [1]. It can be used to determine the composition of the Mars regolith at various depths by insertion into a pre-drilled borehole. The primary requirements and performance metrics for the instrument are to obtain parts-per-million (ppm) lower limits of detection over a wide range of elements in the periodic table (Magnesium to Lead). Power consumption during data collection was also measured. The prototype instrument is complete and preliminary testing has been performed. Terrestrial soil Standard Reference Materials were used as the test samples. Detection limits were about 10 weight ppm for most elements, with light elements being higher, up to 1.4 weight percent for magnesium. Power consumption (excluding ground support components) was 12 watts.

Kelliher, Warren C.; Carlberg, Ingrid A.; Elam, W. T.; Willard-Schmoe, Ella

2008-01-01

268

Determination of halide ions in solution by Total Reflection X-ray Fluorescence (TXRF) spectrometry.  

PubMed

An accurate quantitative determination of halide ions X (X = Cl, Br, I) in aqueous solution by total reflection X-ray fluorescence (TXRF) is not possible using the traditional acidic internal standards. In general, the standard solutions are highly acidic (e.g., Ga(NO3)3 in HNO3) to avoid precipitation of hydroxides of the standard element and to obtain a stable and reliable standard. In acidic solutions, dissolved halide salts can exchange their cation for a proton. The resulting volatile HX compounds can evaporate during the drying procedure of the TXRF sample preparation. In this technical note, we show that an alkaline Cu(NH3)4(NO3)2 standard can be used for the determination of chlorine, bromine and iodine without facing problems of HX evaporation. PMID:24387144

Vander Hoogerstraete, Tom; Jamar, Steven; Wellens, Sil; Binnemans, Koen

2014-02-01

269

[Development of ceramic standard samples used for X-ray fluorescence spectrometric analysis].  

PubMed

The preparation of 17 kinds of ceramic standard samples (CSS) is introduced briefly in the present paper, and the experimental results of the sintered CSS by using EPMA and XRF are discussed in detail. The conclusions can be mainlydrawn that the CSS, which have high density, low water absorption and good homogeneity of element distribution, have similar phase structure (or matrix) to the bodies of ancient ceramics, and perfectly meet the requirements of being used as ceramic standard samples. This set of CSS are expected to play an important role in x-ray fluorescence spectrometric quantitative analysis of Na2O, MgO, Al2O3, SiO2, K2O, CaO, TiO2 and Fe2O3 in the body of ancient ceramics and can provide accurate and reliable data for study and identification of ancient ceramics. PMID:21284202

Zhu, Ji-hao; Feng, Song-lin; Chu, Feng-you; Feng, Xiang-qia; Xie, Guo-xi; Yan, Ling-tong; Li, Liz

2010-11-01

270

X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy analysis of Roman silver denarii  

NASA Astrophysics Data System (ADS)

In this paper we present the results of a study performed on a large collection of silver Roman republican denarii, encompassing about two centuries of history. The joint use of Laser-Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF) spectroscopy allowed for an accurate determination of the coins' elemental composition; the measurements, performed mostly in situ at the 'Monetiere' in Florence, revealed a striking connection between the 'quality' of the silver alloy and some crucial contemporary events. This finding was used to classify a group of denarii whose dating was otherwise impossible. The comparison with other contemporary denarii disproves a recent theory on the origin of the so called 'serrated' denarii (denarii showing notched chisel marks on the edge of the coin).

Pardini, L.; El Hassan, A.; Ferretti, M.; Foresta, A.; Legnaioli, S.; Lorenzetti, G.; Nebbia, E.; Catalli, F.; Harith, M. A.; Diaz Pace, D.; Anabitarte Garcia, F.; Scuotto, M.; Palleschi, V.

2012-08-01

271

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

272

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

273

Portable X-ray Fluorescence Spectrometry for the analyses of Cultural Heritage  

NASA Astrophysics Data System (ADS)

Field Portable Energy Dispersive X Ray Fluorescence (FP-EDXRF) is particularly useful to analyze works of art, mainly because of his noninvasive and multielemental capability. In many situations FP-EDXRF is the only non invasive technique that can be realistically used to gain some information about the chemical composition of precious and unique objects. Many kind of works, such as paintings, bronzes, precious metals alloys, inks, stones, stamps and more can be studied using a field portable EDXRF system. This manuscript highlights some drawbacks that have to be kept in mind to fulfill a valid measurement such as the need for other backup methods to support portable XRF results or the problem of the non-homogeneity of the sample. This manuscript will also present three examples to demonstrate the usefulness of FP-EDXRF with paintings on canvas, ancient bronzes and sulfur surface analyses.

Ridolfi, S.

2012-07-01

274

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

275

Synchrotron X-ray fluorescent analysis application in biogeochemical investigations in Yakutia  

NASA Astrophysics Data System (ADS)

Large possibilities of synchrotron X-ray fluorescent analysis (SR-XRFA), along with the simple preparation of biological samples, allowed us to carry out valuable biogeochemical investigations in Yakutia during the years 2002-2008. New data on the accumulation of macroelements K, Ca, Fe, Mn, biophilic microelements Cu, Zn, Mo, chalcophilous Ni, Pb, Ag, As, Sb, rare lithophilous Rb, Sr, Zr, Y, Nb, scattered chalcophilous Ga, Ge, Se, Cd, Te, Tl in the tissues of larch (Larix cajanderi Mayr.), mosses and lichens (Cladina genus, Dicranum genus, Hylocomium) were obtained. A connection between the elemental composition of larch tissues and the composition of bed rocks was revealed; a comparison with the elemental composition of mosses and lichens was carried out.

Artamonova, S. Yu.; Kolmogorov, Yu. P.

2009-05-01

276

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

277

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

278

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

SciTech Connect

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

Wheeler, B.D.

1982-01-01

279

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

280

Reconstruction of Elemental Distribution Images from Synchrotron Radiation X-Ray Fluorescence Spectra  

NASA Astrophysics Data System (ADS)

Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) is a powerful technique for studying trace elements in biological samples and other materials in general. Its features including capability to perform measurements in air and water, noncontact and nondestructive assay are superior to other elemental analysis techniques. In this study, a technique for reconstructing elemental distribution mapping of trace elements from spectral data was developed. The reconstruction was made possible by using the measured fluorescent signals to obtain local differences in elemental concentrations. The proposed technique features interpolation and background subtraction using matrix transformations of the spectral data to produce an enhanced distribution images. It is achieved by employing polychromatic or monochromatic color assignments proportional to the fluorescence intensities for displaying single-element or multiple-element distributions respectively. Some typical applications (i.e., macrophage and tissue surrounding an implant) were presented and the samples were imaged using the proposed method. The distribution images of the trace elements of the selected samples were used in conjunction with other analytical techniques to draw relevant observations, which cannot be achieved using conventional techniques such as metallic uptake and corresponding cellular response. The elemental distribution images produced from this study were found to have better quality compared to images produced using other analytical techniques (e.g., SIMS, PIXE, XPS, etc).

Toque, Jay Arre; Ide-Ektessabi, Ari

281

Advanced gated x-ray imagers for experiments at the National Ignition Facility  

NASA Astrophysics Data System (ADS)

X-ray imaging is integral to the measurement of the properties of hot plasmas. To this end, a suite of gated x-ray imagers have been developed for use in a wide range of experiments at the National Ignition Facility (NIF). These instruments are sensitive to x-rays over the range of 0.7-90keV and can acquire images at 20ps intervals for source intensities ranging over several orders of magnitude. We review the design, technology, and construction of these instruments and present recent results obtained from NIF experiments in which gated x-ray imagers have played a key role. The radiation environment associated with Inertial Confinement Fusion (ICF) experiments presents unique challenges for x-ray imaging. We report on the performance of gated imagers that have been optimized for this harsh environment and describe diagnostics to be deployed in the near future that will provide x-ray images of imploding ICF capsules in the presence of backgrounds associated with neutron yields above 1016. Such images will provide crucial data that will enable even higher neutron yields and successful ignition.

Glenn, S.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Celeste, J.; Heeter, R.; Hagmann, C.; Holder, J.; Izumi, N.; Kilkenny, J. D.; Kimbrough, J.; Kyrala, G. A.; Simanovskaia, N.; Tommasini, R.

2011-09-01

282

Measurement of K x-ray fluorescence parameters in elements with 24?Z?65 in an external magnetic field  

NASA Astrophysics Data System (ADS)

The effect of the external magnetic field has been investigated on the K x-ray fluorescence parameters (K?, K? and total K x-rays fluorescence cross sections, fluorescence yields, IK?/IK? intensity ratios and K shell level widths) for 25 elements with 24?Z?65 by using an energy dispersive x-ray fluorescence spectrometer. The samples were irradiated by using the gamma rays of 59.537 keV emitted from 241Am radioisotope source of 100 mCi. The external magnetic fields have been applied in two opposite directions and the magnitude of the external magnetic field has been fixed at +0.75 T and -0.75 T. For B=0, the measured K shell fluorescence parameters have been compared with the experimental and theoretical data in literature. The results show that the fluorescence parameters such as fluorescence cross section, fluorescence yield, intensity ratio, spectral linewidth and radiation rates can change when the irradiation is conducted in the external magnetic field.

Demir, D.; ?ahin, Y.

2013-04-01

283

Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments  

SciTech Connect

A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 A) 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 the Mylar and the copper foils irradiated at 10{sup 15} W/cm{sup 2}. The instrument demonstrated a resolving power of {approx}120 at 19 A 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 resolutions of this diagnostic make it useful for studies of high temperature plasmas.

Cone, K. V.; Park, J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); University of California at Davis, Davis, California 95616 (United States); Dunn, J.; Schneider, M. B.; Brown, G. V.; Emig, J.; James, D. L.; May, M. J.; Shepherd, R.; Widmann, K. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Baldis, H. A. [University of California at Davis, Davis, California 95616 (United States)

2010-10-15

284

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

285

X-ray scattering experiments on solid helium  

NASA Astrophysics Data System (ADS)

Using x-ray synchrotron radiation, we have studied the nature of crystals of solid ^4He at temperatures down to 50 mK. Measurements of peak intensities and lattice parameters do not show indications of the supersolid transition. Between 50 mK and 0.6K the relative change in the lattice parameters is less than 2x10-5 and that in less than 4x10-3. Scanning with a small (down to 10 x 10 ?m^2) beam, we resolve a mosaic structure within these crystals consistent with numerous small angle grain boundaries. The mosaic shows significant motion even at temperatures far from melting. When grown in aerogel, solid ^4He polycrystalline, with an hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to the expectation that the highly disordered solid will have a large supersolid fraction, torsional oscillator measurements show a behavior that is strikingly similar to high quality crystals grown from the superfluid phase. The low temperature supersolid fraction is only ˜3x10-4 and the onset temperature is ˜ 100 mK. Work done in collaboration with C.A. Burns, M.H.W. Chan, C.N. Kodituwakku, L.B. Lurio, A. Said and J.T. West.

Mulders, Norbert

2009-03-01

286

Micro-x-ray fluorescence, micro-x-ray absorption spectroscopy, and micro-x-ray diffraction investigation of lead speciation after the addition of different phosphorus amendments to a smelter-contaminated soil.  

PubMed

The stabilization of Pb on additions of P to contaminated soils and mine spoil materials has been well documented. It is clear from the literature that different P sources result in different efficacies of Pb stabilization in the same contaminated material. We hypothesized that the differences in the efficacy of Pb stabilization in contaminated soils on fluid or granular P amendment addition is due to different P reaction processes in and around fertilizer granules and fluid droplets. We used a combination of several synchrotron-based techniques (i.e., spatially resolved micro-X-ray fluorescence, micro-X-ray absorption near-edge structure spectroscopy, and micro-X-ray diffraction) to speciate Pb at two incubation times in a smelter-contaminated soil on addition of several fluid and granular P amendments. The results indicated that the Pb phosphate mineral plumbogummite was an intermediate phase of pyromorphite formation. Additionally, all fluid and granular P sources were able to induce Pb phosphate formation, but fluid phosphoric acid (PA) was the most effective with time and distance from the treatment. Granular phosphate rock and triple super phosphate (TSP) amendments reacted to generate Pb phosphate minerals, with TSP being more effective at greater distances from the point of application. As a result, PA and TSP were the most effective P amendments at inducing Pb phosphate formation, but caution needs to be exercised when adding large amounts of soluble P to the environment. PMID:25602650

Baker, Lucas R; Pierzynski, Gary M; Hettiarachchi, Ganga M; Scheckel, Kirk G; Newville, Matthew

2014-03-01

287

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

288

The secondary X-ray fluorescence and absorption near the interface of multi-material: case of EDS microanalysis.  

PubMed

A simple model is proposed to take into account secondary X-ray fluorescence and absorption effects near the interface. This model is based on the investigation of the shape change of the first derivative equation that can fit the sigmoidal EDS profile obtained when a high vacuum electron beam passes through the interface of two adjacent materials. The contribution of the photoelectric absorption of primary X-rays (characteristic and Bremsstrahlung) and the secondary fluorescence on the degradation of the X-ray spatial resolution can be easily quantified. The close agreement between the simulated (Monte Carlo simulation using the Casino software) and the experimental data serves to assess the reliability of this developed model. PMID:25086233

Zoukel, A; Khouchaf, L

2014-12-01

289

VERIFICATION OF A PARTICLE SIZE CORRECTION METHOD FOR X-RAY FLUORESCENCE SPECTROMETRIC ANALYSIS OF ENVIRONMENTAL SAMPLES  

EPA Science Inventory

Platinum tetraiodide aerosols generated with a spinning disk from solutions in ethanol were used to test a particle size correction factor recently proposed by Criss for the X-ray fluorescence analysis of filter-deposited particulate samples. A set of standards of well-defined pa...

290

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...

291

NOTE In vivo quantification of lead in bone with a portable x-ray fluorescence system--methodology and feasibility  

Microsoft Academic Search

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to

L. H. Nie; S. Sanchez; K. Newton; L. Grodzins; R. O. Cleveland; M. G. Weisskopf

2011-01-01

292

In vivo quantification of lead in bone with a portable x-ray fluorescence system---methodology and feasibility  

Microsoft Academic Search

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to

L. H. Nie; S. Sanchez; K. Newton; L. Grodzins; R. O. Cleveland; M. G. Weisskopf

2011-01-01

293

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...

294

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

295

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...

296

Confocal X-ray Fluorescence (XRF) Microscopy: A New Technique for the Nondestructive Compositional Depth Profiling of Paintings  

E-print Network

#12;Confocal X-ray Fluorescence (XRF) Microscopy: A New Technique for the Nondestructive for sampling. For over 30 years, nondestructive characterization of buried paint layers has been carried out. Recently, researchers have attempted to extend the use of traditional, non-destructive characterization

Gruner, Sol M.

297

Screening heavy metals levels in hair of sanitation workers by X-ray fluorescence Jauharah Md Khudzari b,1  

E-print Network

Screening heavy metals levels in hair of sanitation workers by X-ray fluorescence analysis Jauharah online 28 July 2012 Keywords: Hair Heavy metal EDXRF As Hg Pb a b s t r a c t This work presents a study of human hair as a bio-indicator for detection of heavy metals as part of environmental health surveillance

Short, Daniel

298

A New In Situ Method of Determining Relative Abundances and Charge States of Implanted Transition Metals in Individual Grains Using Synchrotron X-Ray Fluorescence  

SciTech Connect

We report on a new in situ method of determining relative abundances and charge states of implanted transition metals in individual grains using synchrotron X-ray fluorescence. In order to determine in situ the relative abundances and charge states of the transition metals in implanted solar wind in individual lunar plagioclase grains, we have developed a new microbeam x-ray fluorescence method using the synchrotron x-ray microprobe at the Advanced Photon Source (GSECARS sector 13) at Argonne National Laboratory.

Kitts, K.; Sutton, S.; Newville, M. (NIU); (UofC)

2007-03-06

299

INVERSE PROBLEMS IN X-RAY SCIENCE STEFANO MARCHESINI  

E-print Network

-rays absorption/refraction scattering/diffraction (refraction) fluorescence, electrons X-ray interaction) ·Archeology ·Semiconductors (lithography, metrology) ·... 4 #12;ADVANCED LIGHT SOURCE SYNCHROTRON Diffraction - ...................... 5 #12;X-RAY EXPERIMENTS x-rays absorption/refraction scattering/diffraction (refraction

Masci, Frank

300

X-Ray Fluorescence Solvent Detection at the Substrate-Adhesive Interface  

NASA Technical Reports Server (NTRS)

With environmental regulations limiting the use of volatile organic compounds, low-vapor pressure solvents have replaced traditional degreasing solvents for bond substrate preparation. When used to clean and prepare porous bond substrates such as phenolic composites, low vapor pressure solvents can penetrate deep into substrate pore networks and remain there for extended periods. Trapped solvents can interact with applied adhesives either prior to or during cure, potentially compromising bond properties. Currently, methods for characterizing solvent time-depth profiles in bond substrates are limited to bulk gravimetric or sectioning techniques. While sectioning techniques such as microtome allow construction of solvent depth profiles, their depth resolution and reliability are limited by substrate type. Sectioning techniques are particularly limited near the adhesive-substrate interface where depth resolution is further limited by adhesive-substrate hardness and, in the case of a partially cured adhesive, mechanical properties differences. Additionally, sectioning techniques cannot provide information about lateral solvent diffusion. Cross-section component mapping is an alternative method for measuring solvent migration in porous substrates that eliminates the issues associated with sectioning techniques. With cross-section mapping, the solvent-wiped substrate is sectioned perpendicular rather than parallel to the wiped surface, and the sectioned surface is analyzed for the solvent or solvent components of interest using a two-dimensional mapping or imaging technique. Solvent mapping can be performed using either direct or indirect methods. With a direct method, one or more solvent components are mapped using red or Raman spectroscopy together with a moveable sample stage and/or focal plane array detector. With an indirect method, an elemental "tag" not present in the substrate is added to the solvent before the substrate is wiped. Following cross sectioning, the tag element can then be mapped by its characteristic x-ray emission using either x-ray fluorescence, or electron-beam energy-and wavelength-dispersive x-ray spectrometry. The direct mapping techniques avoid issues of different diffusion or migration rates of solvents and elemental tags, while the indirect techniques avoid spectral resolution issues in cases where solvents and substrates have adjacent or overlapping peaks. In this study, cross-section component indirect mapping is being evaluated as a method for measuring migration of d-limonene based solvents in glass-cloth phenolic composite (GCP) prior to and during subsequent bonding and epoxy adhesive cure.

Wurth, Laura; Evans, Kurt; Weber, Bart; Headrick, Sarah

2005-01-01

301

First demonstration of multiplexed X-ray fluorescence computed tomography (XFCT) imaging.  

PubMed

Simultaneous imaging of multiple probes or biomarkers represents a critical step toward high specificity molecular imaging. In this work, we propose to utilize the element-specific nature of the X-ray fluorescence (XRF) signal for imaging multiple elements simultaneously (multiplexing) using XRF computed tomography (XFCT). A 5-mm-diameter pencil beam produced by a polychromatic X-ray source (150 kV, 20 mA) was used to stimulate emission of XRF photons from 2% (weight/volume) gold (Au), gadolinium (Gd), and barium (Ba) embedded within a water phantom. The phantom was translated and rotated relative to the stationary pencil beam in a first-generation CT geometry. The X-ray energy spectrum was collected for 18 s at each position using a cadmium telluride detector. The spectra were then used to isolate the K shell XRF peak and to generate sinograms for the three elements of interest. The distribution and concentration of the three elements were reconstructed with the iterative maximum likelihood expectation maximization algorithm. The linearity between the XFCT intensity and the concentrations of elements of interest was investigated. We found that measured XRF spectra showed sharp peaks characteristic of Au, Gd, and Ba. The narrow full-width at half-maximum (FWHM) of the peaks strongly supports the potential of XFCT for multiplexed imaging of Au, Gd, and Ba ( FWHM(Au,K?1) = 0.619 keV, FWHM(Au,K?2)=1.371 keV , FWHM(Gd,K?)=1.297 keV, FWHM(Gd,K?)=0.974 keV , FWHM(Ba,K?)=0.852 keV, and FWHM(Ba,K?)=0.594 keV ). The distribution of Au, Gd, and Ba in the water phantom was clearly identifiable in the reconstructed XRF images. Our results showed linear relationships between the XRF intensity of each tested element and their concentrations ( R(2)(Au)=0.944 , R(Gd)(2)=0.986, and R(Ba)(2)=0.999), suggesting that XFCT is capable of quantitative imaging. Finally, a transmission CT image was obtained to show the potential of the approach for providing attenuation correction and morphological information. In conclusion, XFCT is a promising modality for multiplexed imaging of high atomic number probes. PMID:23076031

Kuang, Yu; Pratx, Guillem; Bazalova, Magdalena; Meng, Bowen; Qian, Jianguo; Xing, Lei

2013-02-01

302

Multispectral processing of combined visible and x-ray fluorescence imagery in the Archimedes palimpsest  

NASA Astrophysics Data System (ADS)

The Archimedes palimpsest is one of the most significant early texts in the history of science that has survived to the present day. It includes the oldest known copies of text from seven treatises by Archimedes, along with pages from other important historical writings. In the 13th century, the original texts were erased and overwritten by a Christian prayer book, which was used in religious services probably into the 19th century. Since 2001, much of the text from treatises of Archimedes has been transcribed from images taken in reflected visible light and visible fluorescence generated by exposure of the parchment to ultraviolet light. However, these techniques do not work well on all pages of the manuscript, including the badly stained colophon, four pages of the manuscript obscured by icons painted during the first half of the 20th century, and some pages of non-Archimedes texts. Much of the text on the colophon and overpainted pages has been recovered from X-ray fluorescence (XRF) imagery. In this work, the XRF images of one of the other pages were combined with the bands of optical images to create hyperspectral image cubes and processed using standard statistical classification techniques developed for environmental remote sensing to test if this improved the recovery of the original text.

Walvoord, Derek; Bright, Allison; Easton, Roger L., Jr.

2008-02-01

303

Improved micro x-ray fluorescence spectrometer for light element analysis.  

PubMed

Since most available micro x-ray fluorescence (micro-XRF) spectrometers operate in air, which does not allow the analysis of low-Z elements (Z or = 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 microm Cu wire which resulted in a full width at half maximum of 31 microm for Mo Kalpha line (17.44 keV) and 44 microm effective beam size for the Cu K edge and 71 microm effective beam size for the Cu L edge. Lower limits of detection in the picogram range for each spot (or microg/cm(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. PMID:20515145

Smolek, Stephan; Streli, Christina; Zoeger, Norbert; Wobrauschek, Peter

2010-05-01

304

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

305

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

306

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

PubMed

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(12) photons s(-1) into a minimum focal spot size of approximately 3-5 microm 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. PMID:20567085

Barrea, R A; Gore, D; Kujala, N; Karanfil, C; Kozyrenko, S; Heurich, R; Vukonich, M; Huang, R; Paunesku, T; Woloschak, G; Irving, T C

2010-07-01

307

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

308

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

309

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

310

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

311

University of California electron and X-ray experiments on ISEE-3  

NASA Technical Reports Server (NTRS)

The history of the University of California solar and interplanetary electron experiment and the solar X-ray experiment is outlined, and the two instruments used are described. The roles of personnel are mentioned and the data analysis projects completed or begun are summarized. A bibliography is included.

Anderson, K. A.

1981-01-01

312

Solar Maximum Mission experiment - Early results from the soft X-ray polychromator experiment  

NASA Technical Reports Server (NTRS)

It is pointed out that the X-ray polychromator experiment has been in operation on the Solar Maximum Mission satellite for more than three months. Using a number of different modes, the polychromator is observing flares and active regions in the wavelength range 1-23 A. These modes include polychromatic imaging, high resolution line profiles, high dispersion spectra, and light curves with high time-resolution. Data are described and some of the early analysis and interpretation is presented. All the interpretations are based on simple approximate methods; it is noted, however, that in most cases more elaborate and reliable methods are close to being applied.

Gabriel, A. H.; Phillips, K. J. H.; Culhane, J. L.; Bentley, R. D.; Parmar, A. N.; Rapley, C. G.; Acton, L. W.; Leibacher, J. W.; Jordan, C.; Antonucci, E.

1981-01-01

313

Software defined photon counting system for time resolved x-ray experiments  

NASA Astrophysics Data System (ADS)

The time structure of synchrotron radiation allows time resolved experiments with sub-100ps temporal resolution using a pump-probe approach. However, the relaxation time of the samples may require a lower repetition rate of the pump pulse compared to the full repetition rate of the x-ray pulses from the synchrotron. The use of only the x-ray pulse immediately following the pump pulse is not efficient and often requires special operation modes where only a few buckets of the storage ring are filled. We designed a novel software defined photon counting system that allows to implement a variety of pump-probe schemes at the full repetition rate. The high number of photon counters allows to detect the response of the sample at multiple time delays simultaneously, thus improving the efficiency of the experiment. The system has been successfully applied to time resolved scanning transmission x-ray microscopy. However, this technique is applicable more generally.

Acremann, Y.; Chembrolu, V.; Strachan, J. P.; Tyliszczak, T.; Stöhr, J.

2007-01-01

314

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

315

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

316

Pinhole-array x-ray spectrometer for laser-fusion experiments  

SciTech Connect

A pinhole-array x-ray spectrometer for laser-fusion experiments is demonstrated. An array of approximately 300 pinholes is placed in front of a flat-crystal spectrometer, yielding target images at photon energies {approximately}10 eV apart (for photon energies of {approximately}4 to 5 keV). For wideband radiation the images are two dimensional, whereas when a single spectral line is used, the field of view in the direction of dispersion is limited. However, single spectral line images can have a field of view sufficient for imaging the compressed target core. We show the image at the Ti-K{alpha}-line fluorescence from a Ti-doped shell, which we show to be excited by continuum radiation from the compressed core. The K{alpha} image delineates the cold, compressed shell at peak compression, which can otherwise be obtained only through backlighting. In addition, the array provides spectra of high spectral resolution because of the reduction in the effective source size. {copyright} 1998 Optical Society of America

Yaakobi, B.; Marshall, F.J.; Bradley, D.K. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

1998-12-01

317

Further studies using X-ray fluorescence to sample lead contaminated carpeted surfaces.  

PubMed

The sampling of carpeted surfaces to test for lead contamination primarily focuses upon vacuum techniques. Vacuum sampling techniques, however, require time-consuming, expensive laboratory analysis of the dusts obtained and are unable to determine total lead load on the carpet. X-ray fluorescence (XRF) analysis is an on-site, inexpensive, non-destructive, quick technique for predicting metals levels in a variety of media, such as water, soil, filter paper and painted surfaces. A 1992 study of the feasibility of XRF to analyze for lead and soil loadings on carpeted surfaces indicated that XRF can detect lead at a low enough level to warrant further study. This paper expands this earlier study and developes lead and soil loading calibration curves for three different carpet types based upon XRF lead L-beta peak areas and XRF iron and barium K-alpha peak and background areas. Results indicate that variation in the data can be reduced through modifications of the XRF analysis technique, thus reducing the statistically determined detection level, and that carpet type does affect the calibration. Detection levels of approximately 70 mg/m(2) for lead and 5 g/m(2) for soil were obtained. Overall, good agreement was found between results of this study and the earlier one. XRF shows excellent potential for quantitative analysis of lead on carpeted surfaces. PMID:24197726

Bero, B N; von Braun, M C; Knowles, C R; Hammel, J E

1995-06-01

318

Metal ions diffusion through polymeric matrices: A total reflection X-ray fluorescence study  

NASA Astrophysics Data System (ADS)

This work proposes the use of X-ray fluorescence with total reflection geometry to explore the metal ions transport in aqueous hydrophilic polymer solutions. It is centered in the study of polymer concentration influence on ion diffusion. This subject is relevant to various and diverse applications, such as drug controlled release, microbiologic corrosion protection and enhanced oil recovery. It is anticipated that diffusion is influenced by various factors in these systems, including those specific to the diffusing species, such as charge, shape, molecular size, and those related to the structural complexity of the matrix as well as any specific interaction between the diffusing species and the matrix. The diffusion of nitrate salts of Ba and Mn (same charge, different hydrodynamic radii) through water-swollen polymeric solutions and gels in the 0.01% to 1% concentration ranges was investigated. The measurements of the metal concentration were performed by TXRF analysis using the scattered radiation by the sample as internal standard. Results are discussed according to different physical models for solute diffusion in polymeric solutions.

Boeykens, S.; Caracciolo, N.; D'Angelo, M. V.; Vázquez, C.

2006-11-01

319

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

320

Energy dispersive X-ray fluorescence analysis of samples of the Nigerian Zircons  

NASA Astrophysics Data System (ADS)

Energy dispersive X-ray fluorescence technique has been applied to determine the elemental composition of natural zircons obtained from Jos plateau, Nigeria. The zircon samples analysed are of the gem variety with very attractive colour mix. As-received crystals were qualitatively analysed in the bulk/solid form while quantitative analysis was carried out using pellets made from pulverised and properly homogenised samples. In addition to zirconium which is the major element with concentrations in the range of 24-26 wt.%, our quantitative analysis showed the presence in minor and trace quantities of 21 other elements/impurities including K, Ca, Mn, Fe, Se, V, Cr, Co, Ni and Rb. In contrast, a number of other elements such as Th and U were observed only in as-received bulk/solid samples, which probably indicates that they are present as inclusions. Scanning electron microscope equipped with EDS analysis confirmed that the major elements present in the samples are zirconium, titanium and oxygen leading to 99.25% ZrSiO 4. The obvious distinction in coloration of the zircon crystals is attributed to the difference in concentrations of some of the impurities the material contained. It is conjectured here also that the internal radioactivity of Nigerian zircon could be due to the presence of U and Th impurities.

Siyanbola, W. O.; Fasasi, A. Y.; Funtua, I. I.; Fasasi, M. K.; Tubosun, I. A.; Pelemo, D. A.; Adesiyan, T. A.

2005-10-01

321

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

322

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

323

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

324

Comparison of gold leaf thickness in Namban folding screens using X-ray fluorescence  

NASA Astrophysics Data System (ADS)

In this work, the thickness of the gold leaf applied in six Japanese folding screens is compared using a nondestructive approach. Four screens belonging to the Momoyama period (~1573-1603) and two screens belonging to the early Edo period (~1603-1868) were analyzed in situ using energy dispersive X-ray fluorescence, and the thickness of the applied gold leaf was evaluated using a methodology based on the attenuation of the different characteristic lines of gold in the gold leaf layer. Considering that the leaf may well not be made of pure gold, we established that, for the purpose of comparing the intensity ratios of the Au lines, layers made with gold leaf of high grade can be considered identical. The gold leaf applied in one of the screens from the Edo period was found to be thinner than the gold leaf applied in the other ones. This is consistent with the development of the beating technology to obtain ever more thin gold leafs.

Pessanha, Sofia; Madeira, Teresa I.; Manso, Marta; Guerra, Mauro; Le Gac, Agnès; Carvalho, Maria Luisa

2014-09-01

325

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

326

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

327

[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

328

Detection of Genetically Altered Copper Levels in Drosophila Tissues by Synchrotron X-Ray Fluorescence Microscopy  

PubMed Central

Tissue-specific manipulation of known copper transport genes in Drosophila tissues results in phenotypes that are presumably due to an alteration in copper levels in the targeted cells. However direct confirmation of this has to date been technically challenging. Measures of cellular copper content such as expression levels of copper-responsive genes or cuproenzyme activity levels, while useful, are indirect. First-generation copper-sensitive fluorophores show promise but currently lack the sensitivity required to detect subtle changes in copper levels. Moreover such techniques do not provide information regarding other relevant biometals such as zinc or iron. Traditional techniques for measuring elemental composition such as inductively coupled plasma mass spectroscopy are not sensitive enough for use with the small tissue amounts available in Drosophila research. Here we present synchrotron x-ray fluorescence microscopy analysis of two different Drosophila tissues, the larval wing imaginal disc, and sectioned adult fly heads and show that this technique can be used to detect changes in tissue copper levels caused by targeted manipulation of known copper homeostasis genes. PMID:22053217

Lye, Jessica C.; Hwang, Joab E. C.; Paterson, David; de Jonge, Martin D.; Howard, Daryl L.; Burke, Richard

2011-01-01

329

Imaging of stroke: a comparison between X-ray fluorescence and magnetic resonance imaging methods  

PubMed Central

A dual imaging approach, combining magnetic resonance imaging to localize lesions and synchrotron rapid scanning X-ray fluorescence (XRF) mapping to localize and quantify calcium, iron and zinc was used to examine one case of recent stroke with hemorrhage and two cases of ischemia 3 and 7 years before death with the latter showing superficial necrosis. In hemorrhagic lesions, more Fe is found accompanied with less Zn. In chronic ischemic lesions, Fe, Zn and Ca are lower indicating that these elements are removed as the normal tissue dies and scar tissue forms. Both susceptibility and T2* maps were calculated to visualize iron in hemorrhages and validated by XRF Ca and Fe maps. The former was superior for imaging iron in hemorrhagic transformation and necrosis but did not capture ischemic lesions. In contrast, T2* could not differentiate Ca from Fe in necrotic tissue but did capture ischemic lesions, complementing the susceptibility mapping. The spatial localization, accurate quantitative data and elemental differentiation shown here could also be valuable for imaging other brain tissue damage with abnormal Ca and Fe content. PMID:22789844

Zheng, Weili; Haacke, E. Mark; Webb, Samuel M.; Nichol, Helen

2013-01-01

330

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

331

Element distribution in the brain sections of rats measured by synchrotron radiation X-ray fluorescence  

NASA Astrophysics Data System (ADS)

The concentration of trace elements in brain sections was measured by synchrotron radiation X-ray fluorescence. The relative concentration was calculated by means of the normalization of Compton scattering intensity approximately 22 keV, after the normalization for collecting time of X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for supporting sample. Furthermore, the statistical evaluation of the element distribution in various regions of the brain sections of the 20-day-old rats was tested. For investigating the distribution of elements in the brain of iodine deficient rats, Wistar rats were fed with iodine deficient diet and deionized water (ID group). The rats were fed the same iodine deficient diet, but drank KIO 3 solution as control (CT group). The results showed that the contents of calcium (Ca) in thalamus (TH) and copper (Cu) and iron (Fe) in cerebral cortex (CX) of ID rats were significantly lower than that of control rats, while the contents of phosphor (P), sulfur (S), potassium (K), rubidium (Rb), bromine (Br), chlorine (Cl), zinc (Zn), Ca and Cu of ID in hippocampus (H) and the contents of Br, Cl, Zn and Ca in cerebral cortex of ID rats were significantly higher. Especially, the difference of Br, Cl, Zn and Ca in H between ID and CT was more significant. The contents of all elements measured in H were higher than (or equal to) CX and/or TH for both groups, except low Cl of the control rats. Furthermore Zn and Cu contents along the hippocampal fissure in both groups were 1.5 ( P<0.001) and 0.87( P<0.03) times higher than in hippocampus, respectively. Considering the results of cluster analysis our study shows that the marked alterations in the spatial distribution of Zn and Ca of ID rats brain during brain development stages. In addition, the effect of the perfusion with 0.9% NaCl solution before taking brain on the distribution of elements in the brain sections was observed and discussed.

Liu, N. Q.; Zhang, F.; Wang, X. F.; Zhang, Z. Y.; Chai, Z. F.; Huang, Y. Y.; He, W.; Zhao, X. Q.; Zuo, A. J.; Yang, R.

2004-02-01

332

Development and characterization of a portable total reflection X-ray fluorescence system using a waveguide for trace elements analysis.  

PubMed

This paper presents a portable total reflection X-ray fluorescence system composed of a 15 W X-ray tube, with a gold anode, a waveguide constituted by two Perspex(®) parallel plates, a Si PIN detector and a quartz optical flat. The critical angle of the total reflection system was experimentally determined by measuring a zinc solution (100 mg/L). The accuracy of the system was checked using SRM 1577b Bovine Liver by NIST as standard reference material. We obtained the absolute detection limits of the following elements: P (450 ± 40 ng), S (200 ± 31 ng), K (30 ± 2.5 ng), Ca (19 ± 3.5 ng), Mn (4.1 ± 0.5 ng), Fe (3.6 ± 0.9 ng), Cu (3.3 ± 0.4 ng) and Zn (3.5 ± 0.3 ng). This paper shows that it is possible to produce total reflection X-ray fluorescence with very compact, efficient, low-cost and easy-to-handle instrumentation using a low-power X-ray tube and a Si PIN compact detector. PMID:25312625

da Costa, Ana Cristina M; de Araújo, Ubiratan B; de Jesus, Edgar F O; Anjos, Marcelino J; Lopes, Ricardo T

2014-01-01

333

X-ray crystal imagers for inertial confinement fusion experiments (invited)  

Microsoft Academic Search

We report on our continued development of high resolution monochromatic x-ray imaging system based on spherically curved crystals. This system can be extensively used in the relevant experiments of the inertial confinement fusion (ICF) program. The system is currently used, but not limited to diagnostics of the targets ablatively accelerated by the Nike KrF laser. A spherically curved quartz crystal

Y. Aglitskiy; T. Lehecka; S. Obenschain; C. Pawley; C. M. Brown; J. Seely

1999-01-01

334

Speciation and localization of Zn in the hyperaccumulator Sedum alfredii by extended X-ray absorption fine structure and micro-X-ray fluorescence.  

PubMed

Differences in metal homeostasis among related plant species can give important information of metal hyperaccumulation mechanisms. Speciation and distribution of Zn were investigated in a hyperaccumulating population of Sedum alfredii by using extended X-ray absorption fine structure and micro-synchrotron X-ray fluorescence (?-XRF), respectively. The hyperaccumulator uses complexation with oxygen donor ligands for Zn storage in leaves and stems, and variations in the Zn speciation was noted in different tissues. The dominant chemical form of Zn in leaves was most probably a complex with malate, the most prevalent organic acid in S. alfredii leaves. In stems, Zn was mainly associated with malate and cell walls, while Zn-citrate and Zn-cell wall complexes dominated in the roots. Two-dimensional ?-XRF images revealed age-dependent differences in Zn localization in S. alfredii stems and leaves. In old leaves of S. alfredii, Zn was high in the midrib, margin regions and the petiole, whereas distribution of Zn was essentially uniform in young leaves. Zinc was preferentially sequestered by cells near vascular bundles in young stems, but was highly localized to vascular bundles and the outer cortex layer of old stems. The results suggest that tissue- and age-dependent variations of Zn speciation and distribution occurred in the hyperaccumulator S. alfredii, with most of the Zn complexed with malate in the leaves, but a shift to cell wall- and citric acid-Zn complexes during transportation and storage in stems and roots. This implies that biotransformation in Zn complexation occurred during transportation and storage processes in the plants of S. alfredii. PMID:25306525

Lu, Lingli; Liao, Xingcheng; Labavitch, John; Yang, Xiaoe; Nelson, Erik; Du, Yonghua; Brown, Patrick H; Tian, Shengke

2014-11-01

335

A Saturn launched X-ray astronomy experiment. Volume 2: S-150  

NASA Technical Reports Server (NTRS)

In order to develop an experiment which would provide previously unknown information at the projected new launch period, a decision was made to modify the S-027 experiment to allow detection of lower energies which had previously not been mapped. The modification basically required that the static counters be replaced with a thin film entrance window gas flow counter which would allow detection of X-ray energies as low as 150 ev. The new experiment designated S-150 was designed to detect X-ray energies over a spectrum of 150 ev to 10 Kev. Photographs of the S-150 experiment are shown. Basically the same signal detection and processing techniques were used on the S-150 experiment as were used on the S-027. For economic reasons much of the S-027 subassembly hardware was used on the new experiment. The main design changes were in the signal detection system and the high energy veto system.

1971-01-01

336

Recent results of synchrotron radiation induced total reflection X-ray fluorescence analysis at HASYLAB, beamline L  

NASA Astrophysics Data System (ADS)

At the Hamburger Synchrotronstrahlungslabor (HASYLAB), Beamline L, a vacuum chamber for synchrotron radiation-induced total reflection X-ray fluorescence analysis, is now available which can easily be installed using the adjustment components for microanalysis present at this beamline. The detector is now in the final version of a Vortex silicon drift detector with 50-mm 2 active area from Radiant Detector Technologies. With the Ni/C multilayer monochromator set to 17 keV extrapolated detection limits of 8 fg were obtained using the 50-mm 2 silicon drift detector with 1000 s live time on a sample containing 100 pg of Ni. Various applications are presented, especially of samples which are available in very small amounts: As synchrotron radiation-induced total reflection X-ray fluorescence analysis is much more sensitive than tube-excited total reflection X-ray fluorescence analysis, the sampling time of aerosol samples can be diminished, resulting in a more precise time resolution of atmospheric events. Aerosols, directly sampled on Si reflectors in an impactor were investigated. A further application was the determination of contamination elements in a slurry of high-purity Al 2O 3. No digestion is required; the sample is pipetted and dried before analysis. A comparison with laboratory total reflection X-ray fluorescence analysis showed the higher sensitivity of synchrotron radiation-induced total reflection X-ray fluorescence analysis, more contamination elements could be detected. Using the Si-111 crystal monochromator also available at beamline L, XANES measurements to determine the chemical state were performed. This is only possible with lower sensitivity as the flux transmitted by the crystal monochromator is about a factor of 100 lower than that transmitted by the multilayer monochromator. Preliminary results of X-ray absorption near-edge structure measurements for As in xylem sap from cucumber plants fed with As(III) and As(V) are reported. Detection limits of 170 ng/l of As in xylem sap were achieved.

Streli, C.; Pepponi, G.; Wobrauschek, P.; Jokubonis, C.; Falkenberg, G.; Záray, G.; Broekaert, J.; Fittschen, U.; Peschel, B.

2006-11-01

337

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

338

Asymmetric Distribution of Metals in the Xenopus Laevis Oocyte: a Synchrotron X-Ray Fluorescence Microprobe Study  

SciTech Connect

The asymmetric distribution of many components of the Xenopus oocyte, including RNA, proteins, and pigment, provides a framework for cellular specialization during development. During maturation, Xenopus oocytes also acquire metals needed for development, but apart from zinc, little is known about their distribution. Synchrotron X-ray fluorescence microprobe was used to map iron, copper, and zinc and the metalloid selenium in a whole oocyte. Iron, zinc, and copper were asymmetrically distributed in the cytoplasm, while selenium and copper were more abundant in the nucleus. A zone of high copper and zinc was seen in the animal pole cytoplasm. Iron was also concentrated in the animal pole but did not colocalize with zinc, copper, or pigment accumulations. This asymmetry of metal deposition may be important for normal development. Synchrotron X-ray fluorescence microprobe will be a useful tool to examine how metals accumulate and redistribute during fertilization and embryonic development.

Popescu, B.F.Gh.; Belak, Z.R.; Ignatyev, K.; Ovsenek, N.; Nichol, H.

2009-06-04

339

Asymmetri Distribution of Metals in the Xenopus Laevis Oocyte: a Synchrotron X-Ray Fluorescence Microprobe Study  

SciTech Connect

The asymmetric distribution of many components of the Xenopus oocyte, including RNA, proteins, and pigment, provides a framework for cellular specialization during development. During maturation, Xenopus oocytes also acquire metals needed for development, but apart from zinc, little is known about their distribution. Synchrotron X-ray fluorescence microprobe was used to map iron, copper, and zinc and the metalloid selenium in a whole oocyte. Iron, zinc, and copper were asymmetrically distributed in the cytoplasm, while selenium and copper were more abundant in the nucleus. A zone of high copper and zinc was seen in the animal pole cytoplasm. Iron was also concentrated in the animal pole but did not colocalize with zinc, copper, or pigment accumulations. This asymmetry of metal deposition may be important for normal development. Synchrotron X-ray fluorescence microprobe will be a useful tool to examine how metals accumulate and redistribute during fertilization and embryonic development.

Popescu, B.F.G.; Belak, Z.R.; Ignatyev, K.; Ovsenek, N.; Nichol, H.; /Saskatchewan U. /SLAC, SSRL

2009-04-29

340

Pb distribution in bones from the Franklin expedition: synchrotron X-ray fluorescence and laser ablation/mass spectroscopy  

NASA Astrophysics Data System (ADS)

Synchrotron micro-X-ray Fluorescence has been used to map the metal distribution in selected bone fragments representative of remains associated with the Franklin expedition. In addition, laser ablation mass spectroscopy using a 25 ?m diameter circular spot was employed to compare the Pb isotope distributions in small regions within the bone fragments. The X-ray Fluorescence mapping shows Pb to be widely distributed in the bone while the Pb isotope ratios obtained by laser ablation within small areas representative of bone with different Pb exchange rates do not show statistically significant differences. These results are inconsistent with the hypothesis that faulty solder seals in tinned meat were the principle source of Pb in the remains of the expedition personnel.

Martin, Ronald Richard; Naftel, Steven; Macfie, Sheila; Jones, Keith; Nelson, Andrew

2013-04-01

341

Determination of bulk etch rate for CR-39 nuclear track detectors using an X-ray fluorescence method  

NASA Astrophysics Data System (ADS)

The thickness of a CR-39 detector is determined using an energy dispersive X-ray fluorescence (EDXRF) method of analysis. The method is based on exciting a suitable target and measuring the intensity of its fluorescence X-ray lines passing through the CR-39 sample in a fixed geometry. By properly selecting the target material, the method succeeds in assessing the thickness change of CR-39 detectors etched for different time intervals. The bulk etch rate ( Vb) may thus be obtained, which is an important parameter for any solid state nuclear track detector. Application of the EDXRF method yielded a value of Vb = (2.01 ± 0.04) ?m h -1 for etching in a 6 N NaOH solution at 75 °C. This value agrees with the bulk etch rate of (1.90 ± 0.03) ?m h -1, obtained by the conventional mass-change method.

Papachristodoulou, C.; Patiris, D.; Ioannides, K. G.

2007-11-01

342

Argon content of the Martian atmosphere at the Viking 1 landing site - Analysis by X-ray fluorescence spectroscopy  

NASA Technical Reports Server (NTRS)

Spectra provided by the Viking 1 X-ray fluorescence spectrometer operating in the calibration mode (without a soil sample in the analysis chamber) were analyzed to determine the argon content of the Martian atmosphere at the landing site. This was found to be less than or equal to 0.15 millibar, or not more than 2% by volume, consistent with data obtained by the entry mass spectrometer and by the mass spectrometer on the lander. It is anticipated that analysis of the K content of surface samples using X-ray fluorescence data will provide information on the evolution of the atmosphere, since most atmospheric argon is apparently produced by decay of K-40.

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

1976-01-01

343

Determination of heavy metal levels in medicinal plant Hemerocallis minor Miller by X-ray fluorescence spectrometry  

Microsoft Academic Search

Contamination of edible plants by toxic metals is a threat for human health. We applied for the first time applied the non-destructive\\u000a X-ray fluorescence spectrometry (XRF) to determine concentrations of heavy metals, i.e., Fe, Ti, Mn, Cr, Cu, Ni, Zn, Sr and\\u000a Ba in plant Hemerocallis minor Miller and soils. Because this plant is used in folk medicine, the metal

Elena V. Chuparina; Tatiana S. Aisueva

2011-01-01

344

DETERMINATION OF SOME TRACE ELEMENTS IN MINERAL SPRING WATERS BY TOTAL REFLECTION X-RAY FLUORESCENCE SPECTROMETRY (TXRF)  

Microsoft Academic Search

Trace metal concentrations of mineral spring waters in central Anatolia, Turkey were investigated by total reflection X-ray fluorescence spectrometry (TXRF). The concentrations of trace heavy-metal ions were quantitatively determined with an internal Ga standard. The element concentrations obtained by TXRF are comparable to results obtained by graphite furnace absorption spectrometry (GFAAS) after separation-preconcentration on an Amberlite XAD-4 column and inductively

Mehmet Dogan; Mustafa Soylak

2002-01-01

345

Determination of trace metals in sea waters of the Albanian coast by energy-dispersive X-ray fluorescence  

Microsoft Academic Search

Preconcentration of trace transition and heavy metal ions by precipitation with APDC has been combined with energy-dispersive X-ray fluorescence for environmental sea water analysis. The preconcentration procedure implies adding of 500 g Mo ion and 10 ml of 1% water solution of APDC to a 500 ml water sample at pH 4, filtering off on a Millipore filter and analyzing

N. Civici

1994-01-01

346

Three-dimensional structures and elemental distributions of Stardust impact tracks using synchrotron microtomography and X-ray fluorescence analysis  

Microsoft Academic Search

Three-dimensional structures and elemental abundances of four impact tracks in silica aerogel keystones of Stardust samples from comet 81P\\/Wild 2 (bulbous track 67 and carrot-type tracks 46, 47, and 68) were examined non-destructively by synchrotron radiation-based microtomography and X-ray fluorescence analysis. Track features, such as lengths, volumes and width as a function of track depth, were obtained quantitatively by tomography.

A. Tsuchiyama; T. Nakamura; T. Okazaki; K. Uesugi; T. Nakano; K. Sakamoto; T. Akaki; Y. Iida; T. Kadono; K. Jogo; Y. Suzuki

2009-01-01

347

Direct analysis of Al2O3 powders by total reflection X-ray fluorescence spectrometry.  

PubMed

A direct analysis procedure for the determination of trace impurities of Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga in Al2O3 ceramic powders by total reflection X-ray fluorescence spectrometry (TXRF) is described. The powders were analysed in the form of slurries containing 1-10 mg mL(-1) of powder. The use of the procedure in the case of powders with differing grain size and for different slurry concentrations was investigated. Three different quantification possibilities were compared, namely the use of Al as a matrix component, the use of Fe as a trace element contained in the sample or of Co added in concentrations of 200 microg g(-1) as internal standard. The homogeneity of elemental distributions in sample layers deposited on the TXRF quartz carriers by evaporating 5 microL of the 10 mg mL(-1) slurries was studied by scanning the 4- to 5-mm-diameter spots of two samples by synchrotron radiation TXRF at Hasylab. For powders with differing graininess but mainly finer than about a few 10 microm, no systematic influence of the grain size on the accuracy of the determinations of Ca, V, Fe, Ni, Cu and Zn could be observed. The measurement precision, however, seemed to be limited by inhomogeneous distributions of the trace elements in the samples as testified by the synchrotron radiation TXRF scans. Detection limits of the developed TXRF procedure for Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga were found to be in the 0.3-7 microg g(-1) range and were shown to increase slightly with the grain size of the samples. Quantification using Al (matrix) as internal standard led to systematically higher values out of the accuracy required, whereas the other two approaches in all cases led to reliable results. PMID:16034618

Peschel, Birgit U; Fittschen, Ursula E A; Pepponi, Giancarlo; Jokubonis, Christoph; Streli, Christina; Wobrauschek, Peter; Falkenberg, Gerald; Broekaert, José A C

2005-08-01

348

Quantification of total element concentrations in soils using total X-ray fluorescence spectroscopy (TXRF).  

PubMed

Total X-ray fluorescence spectroscopy (TXRF) determines concentrations of major and trace elements in multiple media. We developed and tested a method for the use of TXRF for direct quantification of total element concentrations in soils using an S2 PICOFOX™ spectrometer (Bruker AXS Microanalysis GmbH, Germany). We selected 15 contrasting soil samples from across sub-Saharan Africa for element analysis to calibrate the instrument against concentrations determined using the inductively coupled plasma-mass spectroscopy (ICP-MS) standard method. A consistent underestimation of element concentrations using TXRF compared to ICP-MS reference analysis occurred, indicating that spectrometer recalibration was required. Single-element recalibration improved the TXRF spectrometer's sensitivity curve. Subsequent analysis revealed that TXRF determined total element concentrations of Al, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ga accurately (model efficacy/slope close to 1:1 line, and R(2)>0.80) over a wide range of soil samples. Other elements that could be estimated with an acceptable precision (R(2)>0.60) compared with ICP-MS although generally somewhat under- or overestimated were P, Ca, As, Rb, Sr, Y, Pr, Ta and Pb. Even after recalibration, compared to ICP-MS the TXRF spectrometer produced underestimations for elements Na, Mg, Ba, Ce, Hf, La, Nd, W and Sm and overestimations for elements Bi, Tl and Zr. We validated the degree of accuracy of the TXRF analytical method after recalibration using an independent set of 20 soil samples. We also tested the accuracy of the analysis using 2 multi-element standards as well as the method repeatability on replicate samples. The resulting total element concentration repeatability for all elements analyzed were within 10% coefficient of variability after the instrument recalibration except for Cd and Tl. Our findings demonstrate that TXRF could be used as a rapid screening tool for total element concentrations in soils assuming that sufficient calibration measures are followed. PMID:23831788

Towett, Erick K; Shepherd, Keith D; Cadisch, Georg

2013-10-01

349

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

350

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

351

X-ray Fluorescence Imaging of the Hippocampal Formation After Manganese Exposure†  

PubMed Central

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 µg Mn/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 identified substructures of the HPCf 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 µm × 40 µm) and cellular (0.3 µm × 0.3 µm) 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

2013-01-01

352

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

353

Rare earth element concentrations in geological and synthetic samples using synchrotron X-ray fluorescence analysis  

USGS Publications Warehouse

The concentrations of rare earth elements (REEs) in specific mineral grains from the Bayan Obo ore deposit and synthetic high-silica glass samples have been measured by synchrotron X-ray fluorescence (SXRF) analysis using excitation of the REE K lines between 33 and 63 keV. Because SXRF, a nondestructive analytical technique, has much lower minimum detection limits (MDLs) for REEs, it is an important device that extends the in situ analytical capability of electron probe microanalysis (EPMA). The distribution of trace amounts of REEs in common rock-forming minerals, as well as in REE minerals and minerals having minor quantities of REEs, can be analyzed with SXRF. Synchrotron radiation from a bending magnet and a wiggler source at the National Synchrotron Light Source, Brookhaven National Laboratory, was used to excite the REEs. MDLs of 6 ppm (La) to 26 ppm (Lu) for 3600 s in 60-??m-thick standard samples were obtained with a 25-??m diameter wiggler beam. The MDLs for the light REEs were a factor of 10-20 lower than the MDLs obtained with a bending magnet beam. The SXRF REE concentrations in mineral grains greater than 25 ??m compared favorably with measurements using EPMA. Because EPMA offered REE MDLs as low as several hundred ppm, the comparison was limited to the abundant light REEs (La, Ce, Pr, Nd). For trace values of medium and heavy REEs, the SXRF concentrations were in good agreement with measurements using instrumental neutron activation analysis (INAA), a bulk analysis technique. ?? 1993.

Chen, J.R.; Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Rivers, M.L.; Sutton, S.R.; Cygan, G.L.; Grossman, J.N.; Reed, M.J.

1993-01-01

354

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

355

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

SciTech Connect

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 acquisition, and calculation of concentrations are performed continuously using an on-line calculator, Precision and accuracy of the method are discussed and results obtained from ambient measurements are presented. The increased emission of sulfur-containing compounds into the atmosphere has become a major consideration in the design of air pollution monitoring and control strategies. This has stimulated considerable interest in the development of monitoring equipment capable of analyzing the atmospheric aerosol for sulfur-containing compounds. We describe a rapid, sensitive and accurate X-ray fluorescence method for the analysis of elemental sulfur collected from ambient aerosol samples. The instrument includes a dichotomous sampler, air filter transport system and high-sensitivity wavelength dispersive X-ray fluorescence analyzer. An associated calculator/controller enables one to obtain real-time measurements of ambient particulate sulfur concentrations over short time intervals.

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

1980-05-01

356

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

357

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

358

[Determination of Cr, Cu, Zn, Pb and As in soil by field portable X-ray fluorescence spectrometry].  

PubMed

Total concentrations of Cr, Cu, Zn, Pb and As were determined in soil samples from Beijing, Xinjiang, Heilongjiang, Yunnan, and Jiangsu provinces, using field portable X-ray fluorescence spectrometry (XRF). The relationship between XRF analysis results and the concentration of heavy metals in soils was established. The influence of soil particle size and humidity was also considered. Experiments showed that the particle size of soil affected XRF performance. While particle size decreased from 420 to 180 microm, the relative standard deviation (RSD) of XRF detect results reduced from 15.6% to 6.9%. Soil humidity mainly affected the counts of XRF measured. As the soil water content increased from 5% to 252, the analysis result's relative ratio of humid soil samples to oven dried soil samples decreased from 86% to 69%, according with the equation I = 100e(0.015c), where I means relative ratio, and c means water content (R2 = 0.83, n=30). A high degree of linearity was found for all the five heavy metals with the XRF measurement in the range of 0 to 1500 mg x kg(-1). But the linearity equation was not the same among these soils. The linearity equation established with Yunnan soil has a small slope because of higher Fe concentration in soil. The performance of instrument was assessed by comparing XRF analysis result with the standard sample reference, and the result showed that XRF is an effective tool for rapid, quantitative monitoring of soil metal contamination. PMID:21137436

Lu, An-xiang; Wang, Ji-hua; Pan, Li-gang; Han, Ping; Han, Ying

2010-10-01

359

Three-dimensional structures and elemental distributions of Stardust impact tracks using synchrotron microtomography and X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

Three-dimensional structures and elemental abundances of four impact tracks in silica aerogel keystones of Stardust samples from comet 81P/Wild 2 (bulbous track 67 and carrot-type tracks 46, 47, and 68) were examined non-destructively by synchrotron radiation-based microtomography and X-ray fluorescence analysis. Track features, such as lengths, volumes and width as a function of track depth, were obtained quantitatively by tomography. A bulbous portion was present near the track entrance even in carrot-type tracks. Each impact of a cometary dust particle results in the particle disaggregated into small pieces that were widely distributed on the track walls as well as at its terminal. Fe, S, Ca, Ni, and eight minor elements are concentrated in the bulbous portion of track 68 as well as in terminal grains. It was confirmed that bulbous portions and thin tracks were formed by disaggregation of very fine fragile materials and relatively coarse crystalline particles, respectively. The almost constant ratio of whole Fe mass to track volume indicates that the track volume is almost proportional to the impact kinetic energy. The size of the original impactor was estimated from the absolute Fe mass by assuming its Fe content (CI) and bulk density. Relations between the track sizes normalized by the impactor size and impact conditions are roughly consistent with those of previous hypervelocity impact experiments.

Tsuchiyama, A.; Nakamura, T.; Okazaki, T.; Uesugi, K.; Nakano, T.; Sakamoto, K.; Akaki, T.; Iida, Y.; Kadono, T.; Jogo, K.; Suzuki, Y.

2009-08-01

360

Comparison of synchrotron radiation total reflection X-ray fluorescence excitation detection geometries for samples with differing matrices  

NASA Astrophysics Data System (ADS)

The linear polarization of synchrotron radiation (SR) in the orbital plane leads to a background reduction in total reflection X-ray fluorescence (TXRF) analysis if a side-looking detector is used. The optimum orientation of the sample carrier in a SR-TXRF experiment, however, is determined by a trade-off between the exploitation of the linear polarization, the efficiency of excitation and the solid angle of detection and depends on the nature and size of the sample. SR-TXRF measurements on different sample types and using different reflector orientations have been carried out at the Hamburger Synchrotronstrahlungslabor bending magnet beamline L. A NIST standard water sample, a steel sample and an oil standard were analyzed with both a horizontal and a vertical sample carrier orientation. Strongly scattering samples led to lower detection limits with a horizontal reflector whereas weakly scattering samples showed lower detection limits with a vertical reflector configuration. On an intentionally contaminated wafer absolute detection limits of 6.6 fg for Ni could be extrapolated.

Pepponi, G.; Streli, C.; Wobrauschek, P.; Zamini, S.; Zöger, N.; Falkenberg, G.

2003-12-01

361

Critical step-by-step approaches toward correlative fluorescence/soft X-ray cryo-microscopy of adherent mammalian cells.  

PubMed

Soft X-ray cryo-microscopy/tomography with its extraordinary capability to map vitreous cells with high absorption contrast in their full three-dimensional extent, and at a resolution exceeding super-resolution fluorescence microscopy, is a valuable tool for integrative structural cell biology. Focusing on cell biological applications, its ongoing methodological development gained momentum by combining it with fluorescence cryo-microscopy, thus correlating highly resolved structural and specific information in situ. In this chapter, we provide a basic description of the techniques, as well as an overview of equipment and methods available to carry out correlative soft X-ray cryo-tomography experiments on frozen-hydrated cells grown on a planar support. Our aim here is to suggest ways that biologically representative data can be recorded to the highest possible resolution, while also keeping in mind the limitations of the technique during data acquisition and analysis. We have written from our perspective as electron cryo-microscopists/structural cell biologists who have experience using correlative fluorescence/cryoXM/T at synchrotron beamlines presently available for external users in Europe (HZB TXM at U41-FSGM, BESSY II, Berlin/Germany; Carl Zeiss TXMs at MISTRAL, ALBA, Barcelona/Spain, and B24, DLS, Oxfordshire, UK). PMID:25287842

Dent, Kyle C; Hagen, Christoph; Grünewald, Kay

2014-01-01

362

Distorted and Undistorted Atomic Sites in a Ferromagnetic Semiconductor Ge0.6Mn0.4Te Film Determined by X-ray Fluorescence Holography  

NASA Astrophysics Data System (ADS)

Local atomic structures around Ge and Mn atoms in a ferromagnetic semiconductor Ge0.6Mn0.4Te thin film were investigated by performing Ge and Mn K? X-ray fluorescence holographic experiments. The obtained three-dimensional atomic images revealed that the local structure around Mn formed a rock salt lattice, whereas the lattice around Ge was strongly distorted, which is reflected by a rhombohedral structure of GeTe. The undistorted rock salt environment around the Mn atoms is considered to be a key factor allowing for this alloy to exhibit high-temperature ferromagnetism.

Happo, Naohisa; Hayashi, Kouichi; Senba, Shinya; Sato, Hitoshi; Suzuki, Motohiro; Hosokawa, Shinya

2014-11-01

363

Ray-tracing simulations of spherical Johann diffraction spectrometer for in-beam X-ray experiments  

NASA Astrophysics Data System (ADS)

The results of the Monte-Carlo ray-tracing simulations for a Johann-type Bragg spectrometer with spherically curved-crystal designed to detect the X-rays from a fast-moving source are reported. These calculations were performed to optimize the X-ray spectrometer to be used at the gas-target installed at ion storage ring for high-resolution X-ray experiments. In particular, the two-dimensional distributions of detected photons were studied using the Monte-Carlo method both for the stationary and moving X-ray sources, taking into account a detailed description of X-ray source and X-ray diffraction on the crystal as well as a role of the Doppler effect for in-beam experiments. The origin of the asymmetry of observed X-ray profiles was discussed in detail and the procedure to derive a precise (sub-eV) X-ray transition energy for such asymmetric profiles was proposed. The results are important for the investigations of 1s2pP23?1s2sS13 intrashell transition in excited He-like uranium ions in in-beam X-ray experiments.

Jagodzi?ski, P.; Pajek, M.; Bana?, D.; Beyer, H. F.; Trassinelli, M.; Sto¨hlker, Th.

2014-07-01

364

Analysis of beverages for Hg, As, Pb, and Cd with a field portable X-ray fluorescence analyzer.  

PubMed

Analytical capabilities of a handheld X-ray tube analyzer for analysis of beverages were evaluated. Sets of standard solutions for the elements Hg, As, Pb, and Cd were prepared with mass fractions up to 5000 mg/kg. A thirst quencher beverage was spiked with these elements up to mass fractions of 2500 mg/kg. Portions of these solutions were placed in standard X-ray fluorescence (XRF) cells, as well as the original container, and analyzed by using a field portable Innov-X alpha-6000s XRF tube-type analyzer. Uncorrected analyzer output usually yielded qualitative or semiquantitative results for the spiked beverages in X-ray cells. Average correction factors applied to analyzer output yielded accurate (in terms of z-scores) quantitative results for As above 20 mg/kg and qualitative or semiquantitative results for the other elements. Weighted quadratic fit calibrations provided accurate quantitative or semiquantitative results for all elements at levels above 20 mg/kg. The instrument's preset X-ray overlap correction algorithm worked well for the beverage spiked with all four elements. Spiked beverages analyzed through the wall of the original polyethylene terephthalate container produced accurate results within measurement uncertainties after application of "container wall" correction factors. PMID:20480916

Anderson, David L

2010-01-01

365

The origins of radiotherapy: discovery of biological effects of X-rays by Freund in 1897, Kienböck's crucial experiments in 1900, and still it is the dose.  

PubMed

The discovery of X-rays by Wilhelm Conrad Röntgen (1845-1923) was triggered by pursuing an anomalous phenomenon: arousal of fluorescence at a distance from tubes in which cathode rays were elicited, a phenomenon which suggested the existence of a new kind of ray other than cathode rays. The discovery of biological effects of these X-rays by Leopold Freund (1868-1943) was triggered by pursuit of the purportedly useless phenomenon of epilation and dermatitis ensuing from X-ray-diagnostic experiments that others had reported. The crucial experiments performed by Robert Kienböck (1871-1953) entailed the proof that X-ray-dose, not electric phenomena, was the active agent of biological effects ensuing when illuminating the skin using Röntgen tubes. For both the discovery of X-rays and the discovery of their biological effectiveness, priority did not matter, but understanding the physical and medico-biological significance of phenomena that others had ignored as a nuisance. Present discussions about the clinical relevance of improving the dose distribution including protons and other charged particles resemble those around 1900 to a certain degree. PMID:25012643

Widder, Joachim

2014-07-01

366

Polarized x-ray-absorption spectroscopy of the uranyl ion: Comparison of experiment and theory  

SciTech Connect

The x-ray linear dichroism of the uranyl ion (UO{sub 2}{sup 2+}) in uranium {ital L}{sub 3}-edge extended x-ray-absorption fine structure (EXAFS), and {ital L}{sub 1}- and {ital L}{sub 3}-edge x-ray-absorption near-edge structure (XANES), has been investigated both by experiment and theory. A striking polarization dependence is observed in the experimental XANES and EXAFS for an oriented single crystal of uranyl acetate dihydrate [UO{sub 2}(CH{sub 3}CO{sub 2}){sub 2}{center_dot}2H{sub 2}O], with the x-ray polarization vector aligned either parallel or perpendicular to the bond axis of the linear uranyl cation (O-U-O). Single-crystal results are compared to experimental spectra for a polycrystalline uranyl acetate sample and to calculations using the {ital ab} {ital initio} multiple-scattering (MS) code FEFF 6. Theoretical XANES spectra for uranyl fluoride (UO{sub 2}F{sub 2}) reproduce all the features of the measured uranyl acetate spectra. By identifying scattering paths which contribute to individual features in the calculated spectrum, a detailed understanding of the {ital L}{sub 1}-edge XANES is obtained. MS paths within the uranyl cation have a notable influence upon the XANES. The measured {ital L}{sub 3}-edge EXAFS is also influenced by MS, especially when the x-ray polarization is parallel to the uranyl species. These MS contributions are extracted from the total EXAFS and compared to calculations. The best agreement with the isolated MS signal is obtained by using nonoverlapped muffin-tin spheres in the FEFF 6 calculation. This contrasts the {ital L}{sub 1}-edge XANES calculations, in which overlapping was required for the best agreement with experiment. {copyright} {ital 1996 The American Physical Society.}

Hudson, E.A.; Allen, P.G.; Terminello, L.J. [Glenn T. Seaborg Institute for Transactinium Science, Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States)] [Glenn T. Seaborg Institute for Transactinium Science, Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States); Denecke, M.A.; Reich, T. [Institut fuer Radiochemie, Forschungszentrum Rossendorf, Postfach 510119, D-01314 Dresden (Germany)] [Institut fuer Radiochemie, Forschungszentrum Rossendorf, Postfach 510119, D-01314 Dresden (Germany)

1996-07-01

367

Characterization of buried thin films with resonant soft x-ray fluorescence J. A. Carlisle, L. J. Terminello, and E. A. Hudson  

E-print Network

if not impossible to probe using other techniques. Soft x-ray fluorescence SXF spectroscopy using syn- chrotron radiation offers several advantages over surface sensitive spectroscopies for probing the electronic

Himpsel, Franz J.

368

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

369

Selenium Preferentially Accumulates in the Eye Lens Following Embryonic Exposure: A Confocal X-ray Fluorescence Imaging Study.  

PubMed

Maternal transfer of elevated selenium (Se) to offspring is an important route of Se exposure for fish in the natural environment. However, there is a lack of information on the tissue specific spatial distribution and speciation of Se in the early developmental stages of fish, which provide important information about Se toxicokinetics. The effect of maternal transfer of Se was studied by feeding adult zebrafish a Se-elevated or a control diet followed by collection of larvae from both groups. Novel confocal synchrotron-based techniques were used to investigate Se within intact preserved larvae. Confocal X-ray fluorescence imaging was used to compare Se distributions within specific planes of an intact larva from each of the two groups. The elevated Se treatment showed substantially higher Se levels than the control; Se preferentially accumulated to highest levels in the eye lens, with lower levels in the retina, yolk and other tissues. Confocal X-ray absorption spectroscopy was used to determine that the speciation of Se within the eye lens of the intact larva was a selenomethionine-like species. Preferential accumulation of Se in the eye lens may suggest a direct cause-and-effect relationship between exposure to elevated Se and Se-induced ocular impairments reported previously. This study illustrates the effectiveness of confocal X-ray fluorescence methods for investigating trace element distribution and speciation in intact biological specimens. PMID:25607235

Choudhury, Sanjukta; Thomas, Jith K; Sylvain, Nicole J; Ponomarenko, Olena; Gordon, Robert A; Heald, Steve M; Janz, David M; Krone, Patrick H; Coulthard, Ian; George, Graham N; Pickering, Ingrid J

2015-02-17

370

High-resolution manganese X-ray fluorescence spectroscopy. Oxidation-state and spin-state sensitivity  

SciTech Connect

K,[beta] X-ray emission spectra have been recorded for Mn(II), Mn(III), and Mn(IV) compounds with a variety of ligands. The spectra have been interpreted and simulated as atomic multiplets perturbed by a crystal field. The X-ray fluorescence in this region, which results from 3p [yields] 1s transitions, is split between a strong K,[beta][sub 1.3] region and a weaker K[beta][prime] satellite. For Mn(II) complexes, the K[beta][prime] region derives from final states with antiparallel net spins between the 3p[sup 5] hole and the 3d[sup 5] valence shell. The K[beta][sub 1,3] region is dominated by spin-parallel final states. For octahedral high-spin Mn(II), Mn(III), and Mn(IV) complexes, the K,[beta][sub 1.3] peak position shift to lower energy with increasing oxidation state. The K[beta][prime] feature is weaker and broader for the higher oxidation states, and it is almost unobservable for low-spin Mn(III). K[beta] fluorescence is a good probe of Mn spin state and oxidation state. Spin-selective X-ray absorption near-edge spectra, taken by monitoring specific K[beta] features, are illustrated. The potential for site-selective absorption spectroscopy, based on monitoring chemically sensitive K[beta] features, is discussed. 29 refs., 6 figs., 1 tab.

Peng, G.; Wang, X.; Grush, M.M. (Univ. of California, Davis, CA (United States)); deGroot, F.M.F. (Univ. of Nijmegen (Netherlands)); Hamalainen, K. (Univ. of Helsinki (Finland)); Moore, J.A. (Lawrence Berkeley Lab., CA (United States)); Hastings, J.B.; Siddons, D.P. (Brookhaven National Lab., Upton, NY (United States)); Armstrong, W.H. (Boston College, MA (United States)); Mullins, O.C. (Schlumberger-Doll Research, Ridgefield, CT (United States)); Cramer, S.P. (Univ. of California, Davis, CA (United States) Lawrence Berkeley Lab., CA (United States))

1994-04-06

371

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

NASA Astrophysics Data System (ADS)

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 of quantum motions in the x-ray absorption spectra of simple gases. It is found that rare fluctuations in atomic positions can be a cause of features in the spectra of gaseous molecules. In Chapter 3, I explore a novel quantization scheme for the excited and ground state potential surfaces for an isolated nitrogen molecule. This allows for the explicit calculation of the "correct" transition energies and peak widths (i.e. without any adjustable parameters). In Chapter 4, the importance of nuclear motion in molecular solids is investigated for glycine. We find that the inclusion of these motions permits the spectrum to be accurately calculated without any additional adjustable parameters. In Chapter 5, I provide a detailed study of the hydroxide ion solvated in water. There has been recent controversy as to how hydroxide is solvated, with two principal models invoked. I show that some of the computational evidence favoring one model of solvation over the other has been either previously obtained with inadequate precision or via a method that is systematically biased. In Chapter 6, the measured and computed x-ray absorption spectra of pyrrole in both the gas phase and when solvated by water are compared. We are able to accurately predict the spectra in both cases. In Chapter 7, the measured x-ray absorption of a series of highly charged cationic salts (YBr3, CrCl3, SnCl4 , LaCl3 and InCl3) solvated in water are presented and explained. In Chapter 8, the measured x-ray absorption spectrum at the nitrogen K-edge of aqueous triglycine is presented, including effects of various salts which can alter its solubility. This is used to show that while x-ray absorption is sensitive to salt interactions with small peptides, it is unlikely to be a sensitive probe for overall protein structures, i.e. to distinguish beta sheet from an alpha helix at the nitrogen K-edge. Finally, in Chapter 9 future directions are discussed.

Schwartz, Craig Philip

372

'Optical' soft x-ray arrays for fluctuation diagnostics in magnetic fusion energy experiments  

SciTech Connect

We are developing large pixel count, fast ({>=}100 kHz) and continuously sampling soft x-ray (SXR) array for the diagnosis of magnetohydrodynamics (MHD) and turbulent fluctuations in magnetic fusion energy plasmas. The arrays are based on efficient scintillators, high thoughput multiclad fiber optics, and multichannel light amplification and integration. Compared to conventional x-ray diode arrays, such systems can provide vastly increased spatial coverage, and access to difficult locations with small neutron noise and damage. An eight-channel array has been built using columnar CsI:Tl as an SXR converter and a multianode photomultiplier tube as photoamplifier. The overall system efficiency is measured using laboratory SXR sources, while the time response and signal-to-noise performance have been evaluated by recording MHD activity from the spherical tori (ST) Current Drive Experiment-Upgrade and National Spherical Torus Experiment, both at Princeton Plasma Physics Laboratory.

Delgado-Aparicio, L.F.; Stutman, D.; Tritz, K.; Finkenthal, M.; Kaita, R.; Roquemore, L.; Johnson, D.; Majeski, R. [Johns Hopkins University, Department of Physics and Astronomy, Plasma Spectroscopy Group, Bloomberg Center 3400 N. Charles Street, Baltimore, Maryland 21218 (United States); Princeton University Plasma Physics Laboratory, P. O. Box 451, Princeton, New Jersey 08543 (United States)

2004-10-01

373

The use of X-ray fluorescence to detect lead contamination of carpeted surfaces.  

PubMed

The recognition of the hazards to young children of low-level lead intoxication and the widespread distribution of lead in the urban environment have resulted in massive federal, state, and local lead awareness and abatement programs. Two of the most significant exposure routes of lead to young children are the soils and dusts found within the child's home. Most state and federal lead abatement programs deal with lead-based paint contamination but often do not address the issue of soft-surface contamination, such as that of carpets, furniture, and draperies. Carpets can be a reservoir of contaminated soils and dusts; currently, there exists no standard method to test carpeted surfaces for lead contamination.This paper describes a study that uses X-ray fluorescence (XRF) to test carpeted surfaces for lead contamination. XRF technology is the standard technology used in lead-based paint testing and is known to be an accurate technique to test for lead in soils. This study uses a controlled laboratory atmosphere to evaluate this technology; the objectives are to determine: (1) a lower limit of detection for the instrument; and (2) whether soil loading levels can be differentiated by XRF using trace elements also present in the soil. Results indicate that XRF can easily differentiate soil loading levels (g soil/m(2) carpet). The lower limit of detection of soil lead concentration on the carpet is a function of both soil lead concentration and soil loading; therefore, lead loading (mg Pb/m(2)) is a better indicator of detection limit than soil lead concentration. Lead loading detection levels from 108-258 mg Pb/m(2) were obtained, as compared to a level of 10 000 mg/m(2) (1 mg/cm(2)) for lead on painted surfaces as required by theLead-Based Paint Poisoning Prevention Act.XRF technology has the potential to be a fast, inexpensive screening technique for the evaluation of lead contamination on carpeted surfaces. PMID:24220928

Bero, B N; Von Braun, M C; Knowles, C R; Hammel, J E

1993-08-01

374

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.

375

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

376

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

377

Radiation induced noise in x-ray imagers for high-yield inertial confinement fusion experiments  

Microsoft Academic Search

The large fluence of 14-MeV neutrons produced in high-yield inertial confinement fusion (ICF) experiments creates a variety of backgrounds in x-ray imagers viewing the implosion. Secondary charged particles produce background light by Cherenkov emission, phosphor screen excitation and possibly scintillation in the optical components of the imager. In addition, radiation induced optical absorption may lead to attenuation of the signal.

C. Hagmann; J. Ayers; P. M. Bell; J.-L. Bourgade; D. K. Bradley; J. Celeste; C. Cerjan; S. Darbon; J. Emig; B. Felker; S. Glenn; J. Holder; N. Izumi; J. D. Kilkenny; J. Moody; K. Piston; A. Rousseau; V. A. Smalyuk; C. Sorce

2011-01-01

378

Modular deposition chamber for in situ X-ray experiments during RF and DC magnetron sputtering.  

PubMed

A new sputtering system for in situ X-ray experiments during DC and RF magnetron sputtering is described. The outstanding features of the system are the modular design of the vacuum chamber, the adjustable deposition angle, the option for plasma diagnostics, and the UHV sample transfer in order to access complementary surface analysis methods. First in situ diffraction and reflectivity measurements during RF and DC deposition of vanadium carbide demonstrate the performance of the set-up. PMID:22338682

Krause, Bärbel; Darma, Susan; Kaufholz, Marthe; Gräfe, Hans Hellmuth; Ulrich, Sven; Mantilla, Miguel; Weigel, Ralf; Rembold, Steffen; Baumbach, Tilo

2012-03-01

379

Pinhole-array x-ray spectrometer for laser-fusion experiments  

Microsoft Academic Search

A pinhole-array x-ray spectrometer for laser-fusion experiments is demonstrated. An array of approximately 300 pinholes is placed in front of a flat-crystal spectrometer, yielding target images at photon energies 10 eV apart (for photon energies of 4 to 5 keV). For wideband radiation the images are two dimensional, whereas when a single spectral line is used, the field of view

Barukh Yaakobi; Fredric J. Marshall; David K. Bradley

1998-01-01

380

Imaging Detectors for 20-100 ke V X-ray Backlighters in HEDES Petawatt Experiments  

Microsoft Academic Search

We are developing a petawatt laser for use as a high energy backlighter source in the 20 100 keV range. High energy x-ray backlighters will be essential for radiographing High-Energy- Density Experimental Science (HEDES) targets for NIF projects especially to probe implosions and high areal density planar samples. For these experiments we are employing two types of detectors: a columnar

J E Wickersham; P M Bell; J A Koch; O L Landen; J D Moody

2004-01-01

381

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

382

Intrinsic deviations in fluorescence yield detected x-ray absorption spectroscopy: the case of the transition metal L2,3 edges  

NASA Astrophysics Data System (ADS)

Fluorescence yield (FY) detected x-ray absorption spectra (XAS) of 3d transition metal ions are calculated from the integrated 2p3d resonant x-ray emission spectra. The resulting FY-XAS spectra are compared with the normal XAS spectra corresponding to the absorption cross section and significant deviations between the two spectra are found. This implies that the assumption that the FY-XAS spectrum identifies with the XAS spectrum is disproved. Especially for the early transition metal systems the differences between the FY-XAS and XAS are large, due to the opening of inelastic decay channels from selected x-ray absorption final states. The theoretical calculations show that the difference between FY detection and XAS is largest for the detection in depolarized geometry. The calculations are compared with experimental spectra for oxides and coordination compounds for Fe2+, Co2+ and Ni2+ systems. The implications for the sum rules in XAS and magnetic circular dichroism experiments are discussed.

Kurian, Reshmi; Kunnus, Kristjan; Wernet, Philippe; Butorin, Sergei M.; Glatzel, Pieter; de Groot, Frank M. F.

2012-11-01

383

Hard X-ray polarimeter for small satellite: design, feasibility study, and ground experiments  

NASA Astrophysics Data System (ADS)

We make a plan of a hard X-ray polarimetry experiment with a small satellite. Bright point-like sources in 20-80keV are prime targets, for which we will not use focusing optics. Comparing various types of polarimeters, we adopt a scattering type in which anisotropy in scattering directions of photons is employed. After optimization of the design is considered with simplified models of scattering polarimeters, we propose to use segmented scatter targets made of plastic scintillators, with which scattering location is identified by detecting recoiled electrons. Simulations show that recoiled electrons are detectable when incident X-ray energies are above 40keV, for which higher polarimetry sensitivity is obtained. We confirmed the performance of such a polarimeter in experiments at a Synchrotron facility and performed a balloon flight in which a proto type unit of the polarimeter was onboard. We finally discuss feasibility of a small satellite experiment in which many of the polarimeter units will be employed. Twenty five units of the polarimeter enable us to detect hard X-ray polarization of 5-10% for a hundred mCrab sources. Improvement in the sensitivity to detect recoiled electrons will significantly improve the polarimetry sensitivity. We also consider a low energy extension of our system down to below 10keV in order to cover wide energy range.

Hayashida, Kiyoshi; Mihara, Tatehiro; Gunji, Syuichi; Tokanai, Fuyuki

2004-09-01

384

High-resolution X-ray fluorescence and excitation spectroscopy of metalloproteins.  

PubMed

A spectrograph has been developed with sufficient efficiency to make high-resolution fluorescence experiments on metalloproteins possible. The resolution of this spectrometer can reach 0.45 eV at 7.1 keV emission energy. The focus images of this multiple curved-crystal array spectrometer are presented. The chemical sensitivity of Kbeta emission spectra can be used to identify chemical states, and the spin-polarized near-edge structure provides a new measure of the spin density. The high-resolution fluorescence metalloprotein studies should become routine with third-generation synchrotron facilities, and the strength of both site and spin selectivity should complement the structural information from other spectroscopies. PMID:16699236

Wang, X; Grush, M M; Froeschner, A G; Cramer, S P

1997-07-01

385

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...

386

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...

387

Flood control-mesh and X-ray fluorescence spectroscopy based system for city drainage  

Microsoft Academic Search

This paper presents a conceptual model of a system to prevent the clogging of drainage water and avoid spill over onto the roads by utilising a graduated mesh based automatic solid waste separator. The main purpose is to automatically segregate garbage in flowing drainage water, identify and separate plastic using x-ray spectroscopy, collect it and recycle it instead of letting

Anaisha Jaykumar; Swati Padmanabhan

2011-01-01

388

Total Reflection X-ray Fluorescence Analysis (TXRF) using the high flux SAXS camera  

NASA Astrophysics Data System (ADS)

Combining the high photon flux from a rotating anode X-ray tube with an X-ray optical component to focus and monochromatize the X-ray beam is the most promising instrumentation for best detection limits in the modern XRF laboratory. This is realized by using the design of a high flux SAXS camera in combination with a 4 kW high brilliant rotating Cu anode X-ray tube with a graded elliptically bent multilayer and including a new designed module for excitation in total reflection geometry within the beam path. The system can be evacuated thus reducing absorption and scattering of air and removing the argon peak in the spectra. Another novelty is the use of a Peltier cooled drift detector with an energy resolution of 148 eV at 5.9 keV and 5 mm 2 area. For Co detection limits of about 300 fg determined by a single element standard have been achieved. Testing a real sample NIST 1643d led to detection limits in the range of 300 ng/l for the medium Z.

Wobrauschek, P.; Streli, C.; Pepponi, G.; Bergmann, A.; Glatter, O.

2002-04-01

389

Extending synchrotron-based atomic physics experiments into the hard X-ray region  

SciTech Connect

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution the authors discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. They close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells.

LeBrun, T. [Argonne National Lab., IL (United States). Physics Div.

1996-12-31

390

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

391

CMOS Imaging Detectors as X-ray Detectors for Synchrotron Radiation Experiments  

NASA Astrophysics Data System (ADS)

CMOS imagers are matrix-addressed photodiode arrays, which have been utilized in devices such as commercially available digital cameras. The pixel size of CMOS imagers is usually larger than that of CCD and smaller than that of TFT, giving them a unique position. Although CMOS x-ray imaging devices have already become commercially available, they have not been used as an x-ray area detector in synchrotron radiation experiments. We tested performance of a CMOS detector from Rad-icon (Shad-o-Box1024) in medical imaging, small-angle scattering, and protein crystallography experiments. It has pixels of 0.048 mm square, read-out time of 0.45 sec, 12-bit ADC, and requires a frame grabber for image acquisition. The detection area is 5-cm square. It uses a Kodak Min-R scintillator screen as a phosphor. The sensitivity to x-rays with an energy less than 15 keV was low because of the thick window materials. Since the readout noise is high, the dynamic range is limited to 2000. The biggest advantages of this detector are cost-effectiveness (about 10,000 US dollars) and compactness (thickness < 3 cm, weight < 2 kg).

Yagi, Naoto; Yamamoto, Masaki; Uesugi, Kentaro; Inoue, Katsuaki

2004-05-01

392

A portable micro-X-ray fluorescence spectrometer with polycapillary optics and vacuum chamber for archaeometric and other applications  

NASA Astrophysics Data System (ADS)

A portable focused-beam XRF spectrometer was designed, constructed, and manufactured. The spectrometer allows to detect and perform analysis of chemical elements from Na upwards. The system is equipped with a compact vacuum chamber to reduce absorption of both the excitation and the fluorescence radiation in air. A low power Pd-anode tube operated up to 50 kV and 1 mA with a point focus of 400 ?m is used as excitation source. A polycapillary lens with a spot size of about 160 ?m, or a collimator with a 1 mm inner diameter can be used alternatively for either focusing or collimating the primary beam. The fluorescence radiation is collected by an Si drift detector with an active area of 10 mm 2 and equipped with an 8 ?m Be entrance window. A compact vacuum chamber was designed to house the X-ray beam optics and the detector snout. The chamber is attached to the X-ray tube and can be pumped down to 0.1 mbar. A Kapton™ window of 7.5 ?m thickness allows to locate the investigated spot at about 1-2 mm distance outside of the chamber, thus minimizing absorption losses in the excitation and X-ray fluorescence radiation paths. Two lasers pointers are mounted inside the chamber. The laser beams cross at a point outside the chamber in front of the entrance window and coincide with the focal spot of the polycapillary. This paper reports some preliminary results obtained from an in situ analysis of bronze samples as well as a comparison of these data with those given by other laboratory spectrometers and the reference values provided by the Italian bronze foundry Venturi Arte Bologna, Italy.

Buzanich, G.; Wobrauschek, P.; Streli, C.; Markowicz, A.; Wegrzynek, D.; Chinea-Cano, E.; Bamford, S.

2007-11-01

393

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

394

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

395

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

2014-11-01

396

Mirror-based soft x-ray split-and-delay system for femtosecond pump-probe experiments at LCLS  

NASA Astrophysics Data System (ADS)

The unprecedented x-ray peak power available at the Linac Coherent Light Source (LCLS) makes possible, for the first time, experiments in which a sample is excited by x-rays, then probed with a delayed x-ray pulse as the excitation relaxes on the femtosecond timescale. A mirror-based x-ray split and delay (XRSD) instrument under construction at the LCLS will enable forefront science through time-resolved study of fundamental ultrafast x-ray matter interactions in the 500-2000 eV photon energy range. The XRSD will add x-ray pump/x-ray probe capability to the AMO and SXR beamlines, allowing experiments expected to have an impact on basic energy sciences research in areas such as atomic and molecular science, chemical physics, nanoscience, ultrafast science, and imaging. The XRSD splits the LCLS x-ray pulse into two portions by wavefront division, delays one by a user-selected time 0-100 femtoseconds (+/-0.1 fs,) then recombines them at a sample for x-ray pump/x-ray probe experiments on the AMO and SXR beamlines. Two mirrors located immediately after the AMO Kirkpatrick-Baez mirrors will split the FEL wavefront; one of these mirrors will be translated and rotated to produce a variable delay. The energy of both pulses can be independently measured on each shot, aiding data analysis. The XRSD will be integrated into the AMO/SXR control system and data acquisition system for user control. After commissioning, the device will be available for LCLS user proposals at the AMO and SXR endstations.

Murphy, Brendan F.; Castagna, Jean-Charles; Bozek, John D.; Berrah, Nora

2012-10-01

397

High Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy: Detection of Adsorption Sites in Supported Metal Catalysts  

NASA Astrophysics Data System (ADS)

High energy resolution fluorescence detection (HERFD) X-ray adsorption spectroscopy (XAS) is demonstrated as a new tool to identify the geometry of metal adsorption sites and the orbitals involved in bonding. The type of CO adsorption site on a nanoparticular Pt-Al2O3 catalyst is determined. The orbitals involved in the Pt — CO bonding are identified using theoretical FEFF8.0 calculations. In situ application of HERFD XAS is applicable to a large number of catalytic systems and will provide fundamental insights in structure — performance relationships.

Tromp, Moniek; van Bokhoven, Jeroen A.; Safonova, Olga V.; De Groot, Frank M. F.; Evans, John; Glatzel, Pieter

2007-02-01

398

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

399

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

400

Use of portable X-ray fluorescence spectrometry for environmental quality assessment of peri-urban agriculture.  

PubMed

Urban expansion into traditional agricultural lands has augmented the potential for heavy metal contamination of soils. This study examined the utility of field portable X-ray fluorescence (PXRF) spectrometry for evaluating the environmental quality of sugarcane fields near two industrial complexes in Louisiana, USA. Results indicated that PXRF provided quality results of heavy metal levels comparable to traditional laboratory analysis. When coupled with global positioning system technology, the use of PXRF allows for on-site interpolation of heavy metal levels in a matter of minutes. Field portable XRF was shown to be an effective tool for rapid assessment of heavy metals in soils of peri-urban agricultural areas. PMID:21384116

Weindorf, David C; Zhu, Yuanda; Chakraborty, Somsubhra; Bakr, Noura; Huang, Biao

2012-01-01

401

Application of instrumental neutron activation and X-ray fluorescence analysis to the examination of objects of art  

NASA Astrophysics Data System (ADS)

In the Institute of Nuclear Chemistry and Technology in Warsaw in collaboration with the Department of Preservation and Restoration of Works of Art of the Academy of Fine Arts in Cracow and National Museum in Warsaw systematic studies using nuclear methods, particulary instrumental neutron activation analysis and X-ray fluorescence analysis, have been carried out on the panel paintings from the Krakowska- Nowosadecka School and Silesian School of the period from the XIV-XVII century, Chinese and Thai porcelains and mummies fillings of Egyptian sarcophagi. These studies will provide new data to the existing data base, will permit to compare materials used by various schools and individual artists.

Panczyk, E.; Ligeza, M.; Walis, L.

1999-01-01

402

Exploring RNA oligomerization and ligand binding by fluorescence correlation spectroscopy and small angle X-ray scattering.  

PubMed

RNA forms defined structures and binds specifically to target molecules. The combination of data which results from fluorescence correlation spectroscopy (FCS) and small angle X-ray scattering (SAXS) measurements can be used to determine intermolecular interactions between RNA and its binding partners. To define oligomerization states of free RNA and its complexes with bound target molecules, hydrodynamic radii, radii of gyration as well as the maximum sizes of the components have to be determined and compared. Furthermore, the program OLIGOMER allows calculating the portions of monomeric and dimeric RNA, for instance, within a mixture. PMID:24136613

Magbanua, Eileen; Konarev, Petr V; Svergun, Dmitri I; Hahn, Ulrich

2014-01-01

403

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

404

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

405

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

406

Scanning X-ray fluorescent elemental microanalysis with synchrotron radiation in geochemical research  

NASA Astrophysics Data System (ADS)

The traditional XRF analysis with high limits of detection is limited in application for geochemical researches. Use of synchrotron radiation considerably expands its opportunities [1]. Since 1985 in BINP analytical works with syncrotron radiation from storage ring VEPP-3 are carried out. A plenty of methodical and research works with geochemical samples has been executed. The range of energy excitation 15 - 50 keV is now accessible, that allows to determine the following elements in geological samples weight from 1 mg: P, S, Cl, K, Ca, Ti (LD=50 ppm, St.dev.=5 ppm); V, Cr, Mn, Fe, Co, Ni (LD=5 ppm, St.dev.=0.5 ppm); Cu, Zn, Ga, Ge, As, Se (LD=0.5 ppm, St.dev.=0.05 ppm); Br, Rb, Sr, Y, Zr, Nb, Mo (LD=0.1 ppm, St.dev.=0.03 ppm); Ru, Rh, Pd, Ag (LD=0.05 ppm, St.dev.=0.01 ppm); Cd, In, Sn, Sb, Te, I (LD=0.1 ppm, St.dev.=0.03 ppm); Ba, La, Ce, Nd, Sm (LD=1.0 ppm, St.dev.=0.15 ppm); Pb, Bi, Th, U (LD=1 ppm, St.dev.=0.1 ppm). The analysis is carried out in some stages with use various energy of excitation (usually - 15-18, 22 - 25 and 40-45 keV). The first instrument of scanning X-ray fluorescent elemental microanalysis with synchrotron radiation from storage ring VEPP-3 (scan.XRFA-SR) was founded in BINP SB RAS in the 1988 and applied to study the spatial distribution of elements in geological samples [2]. Scan.XRFA-SR was used in paleoclimate reconstructions based on high-resolution sediments and tree-rings analysis [3, 4, 5]. Unique opportunities of XRF SR allow to carry out scanning microanalysis with spatial resolution ~ 10 micron. The set of analyzed elements and range of concentration are determined by selection of energy of excitation and time of measurement in a point. In recent years, has been studied many different geological samples: diamonds, xenolith, ferromanganese nodules, bottom sediments. Studies have demonstrated the unique ability of scanning XRFA-SR: a simultaneous analysis of more than 30 chemical elements with a spatial resolution of 10-50 microns. [1] V. B. Baryshev et all. Rev. Sci. Instrum. 60 (1989) N7 2456. [2] A. V. Daryin et all. Nucl. Instrum. and Meth. A308 (1991) 318. [3] K.V. Zolotarev et all. Nucl. Instrum. and Meth. A470 (2001),376. [4] A.V. Daryin et all. Nucl. Instrum. and Meth. A 543 (2005) 255. [5] I.A. Kalugin et all. Quaternary Research 67 (2007) 400.

Darin, A.; Kalugin, I.; Zolotarev, K.

2009-04-01

407

ReSPEKT Energy-Dispersive x-Ray Fluorescence Composition Analyzer  

Microsoft Academic Search

The sensitivity of x-ray spectrometers is low when analyzing liquid objects. The lower limit of detection ordinarily is several mg\\/liter, which is inadequate for certain analytical problems. Thus, the maximum admissable concentration of metals in drinking water is 0.01?0.1 mg\\/liter. Consequently, different methods of concentration are used ? evaporation of the initial solution, passage through special filters followed by analysis,

I. A. Tolokonnikov

2003-01-01

408

Use of Synchrotron X-ray Fluorescence to Measure Trace Metal Distribution in the Brain  

Microsoft Academic Search

X26A, National Synchrotron Light Source, was used to quantitatively evaluate the spatial distribution of trace metals, such as Zn and Cu, in brain tissue. X-ray microprobe techniques offer distinct advantages over other analytical methods by allowing analyses to be done in-situ with little or no chemical pretreatment and low detection limits (about 1 ppm). In the context of neuroscience, SXRF

D. Linkous; J. M. Flinn; A. Lanzirotti; C. Frederickson; B. F. Jones; P. M. Bertsch

2002-01-01

409

Scanning-free grazing emission x-ray fluorescence by means of an angular dispersive arrangement with a two-dimensional position-sensitive area detector  

NASA Astrophysics Data System (ADS)

We report on the application of a two-dimensional position-sensitive area detector towards grazing emission x-ray fluorescence (GEXRF) spectroscopy. GEXRF allows for surface-sensitive studies with nanometer-scale accuracy in the depth direction by measuring the intensity variation of an x-ray fluorescence line with the grazing emission angle. The presented experimental setup is based on a fixed sample-detector arrangement and does not require any moving components. We show that the dispersion of the grazing emission angle along a position-sensitive detector allows to acquire with an excellent angular resolution a full GEXRF profile in a single measurement. Moreover, the use of a two-dimensional detector allows to perform experiments with an increased solid angle of detection per emission angle. This results in combination with the nonsequential and simultaneous acquisition of the GEXRF profiles of different emission lines in considerably reduced acquisition times. The realization, the demands, and the main characteristics of the scanning-free GEXRF setup will be presented. A few experimental examples will serve to illustrate the analytical possibilities offered by the presented setup.

Kayser, Y.; Szlachetko, J.; Sà, J.

2013-12-01

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 new spectrometer for grazing incidence X-ray fluorescence for the characterization of Arsenic implants and Hf based high-k layers  

NASA Astrophysics Data System (ADS)

Grazing Incidence X-ray Fluorescence Analysis (GIXRF) is a powerful technique for depth-profiling and characterization of thin layers in depths up to a few hundred nanometers. By measurement of fluorescence signals at various incidence angles Grazing Incidence X-ray Fluorescence Analysis provides information on depth distribution and total dose of the elements in the layers. The technique is very sensitive even in depths of a few nanometers. As Grazing Incidence X-ray Fluorescence Analysis does not provide unambigous depth profile information and needs a realistic input depth profile for fitting, in the context of the EC funded European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis (ANNA) Grazing Incidence X-ray Fluorescence Analysis is used as a complementary technique to Secondary Ion Mass Spectrometry (SIMS) for the characterization of Ultra Shallow Junctions (USJ). A measuring chamber was designed, constructed and tested to meet the requirements of Grazing Incidence X-ray Fluorescence Analysis. A measurement protocol was developed and tested. Some results for As implants as well as Hf based high k layers on Silicon are shown. For the determination of the bulk As content of the wafers, Instrumental Neutron Activation Analysis has also been applied for comparison.

Ingerle, D.; Meirer, F.; Zoeger, N.; Pepponi, G.; Giubertoni, D.; Steinhauser, G.; Wobrauschek, P.; Streli, C.

2010-06-01

412

A Saturn launched X-ray astronomy experiment. Volume 1: S-027  

NASA Technical Reports Server (NTRS)

The S-027 X-Ray Astronomy Experiment originally proposed in early 1966, was developed to detect X-rays in the 2 keV to 10 keV range. Both a prototype unit and flight unit were constructed with the prototype unit also serving as the engineering model, the qualification test unit, and after refurbishment, as the back-up flight unit. Two Ground Support Equipment consoles were built to verify the experiment operation. A photograph of one experiment package with its Ground Support Equipment is shown. The S-027 experiment was scheduled for launch in 1968/69 and although both units were completed and tested to the extent that either would be ready for the scheduled launch, delays in the space program resulted in a launch date slip of several years. When the 1968/69 launch delay became official, provisions were made for storage of the two experiment packages at SCI Electronics in Huntsville, Alabama until a new launch date could be established.

1971-01-01

413

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, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.

Conti, C. C.; Anjos, M. J.; Salgado, C. M.

2014-09-01

414

X-ray--optical cross correlator for gas-phase experiments at the LCLS free-electron laser  

NASA Astrophysics Data System (ADS)

X-ray--optical pump--probe experiments at the Linac Coherent Light Source (LCLS) have so far been limited to a time resolution of 280,s fwhm due to timing jitter between the accelerator-based free-electron laser (FEL) and optical lasers. We have implemented a single-shot cross-correlator for femtosecond x-ray and infrared pulses. An independent reference experiment relying only on the pulse arrival time information from the cross-correlator shows a time resolution better than 50,s fwhm (22,s rms) and also yields a direct measurement of the maximal x-ray pulse length. The improved time resolution enables ultrafast pump--probe experiments with x-ray pulses from LCLS and other FEL sources. Reference: S. Schorb et al., Appl. Phys. Lett. 2012 in press

Schorb, Sebastian; Gorkhover, T.; Cryan, J. P.; Glownia, J. M.; Bionta, M. R.; Coffee, R. N.; Erk, B.; Boll, R.; Schmidt, C.; Rolles, D.; Rudenko, A.; Rouzee, A.; Swiggers, M.; Carron, S.; Castagna, J.-C.; Bozek, J. D.; Messerschmidt, M.; Schlotter, W. F.; Bostedt, C.

2012-06-01

415

Folic acid-conjugated silica capped gold nanoclusters for targeted fluorescence/X-ray computed tomography imaging  

PubMed Central

Background Gastric cancer is 2th most common cancer in China, and is still the second most common cause of cancer-related death in the world. Successful development of safe and effective nanoprobes for in vivo gastric cancer targeting imaging is a big challenge. This study is aimed to develop folic acid (FA)-conjugated silica coated gold nanoclusters (AuNCs) for targeted dual-modal fluorescent and X-ray computed tomography imaging (CT) of in vivo gastric cancer cells. Method AuNCs were prepared, silica was coated on the surface of AuNCs, then folic acid was covalently anchored on the surface of AuNCs, resultant FA-conjugated AuNCs@SiO2 nanoprobes were investigated their cytotoxicity by MTT method, and their targeted ability to FR(+) MGC803 cells and FR(?) GES-1 cells. Nude mice model loaded with MGC803 cells were prepared, prepared nanoprobes were injected into nude mice via tail vein, and then were imaged by fluorescent and X-ray computed tomography (CT) imaging. Results FA-conjugated AuNCs@SiO2 nanoprobes exhibited good biocompatibility, and could target actively the FR(+) MGC-803 cells and in vivo gastric cancer tissues with 5 mm in diameter in nude mice models, exhibited excellent red emitting fluorescence imaging and CT imaging. Conclusion The high-performance FA-conjugated AuNCs@SiO2 nanoprobes can target in vivo gastric cancer cells, can be used for fluorescent and CT dual-mode imaging, and may own great potential in applications such as targeted dual-mode imaging of in vivo early gastric cancer and other tumors with FR positive expression in near future. PMID:23718865

2013-01-01

416

Development of an Energetic X-Ray Imaging Telescope Experiment (EXITE) and Associated Balloon Gondola System  

NASA Technical Reports Server (NTRS)

This is the Final Report for grant NAGW-624, which was our original grant to develop the Energetic X- ray Imaging Telescope Experiment (EXITE) and Associated Balloon Gondola. The EXITE grant was changed over to a new grant (from GSFC), NAG5-5103, beginning in FY97 and is currently very much continuing under that grant. The Final Report presented here then covers the EXITE development under the original grant, which in fact continued (with a 1 year no-cost extension) through December 31, 1997.

1997-01-01