X-ray fluorescence mapping

Fig. 2. Low and high resolution maps of polysaccharides distribution in the Goniastrera skeleton (a) Polished surface of wall and septa (b) Low resolution X-ray fluorescence map higher concentrations of S-polysaccharides are visible in EMZ of wall and septa (c) High resolution X-ray fluorescence map in fibrous tissue. Evidence of the layered distribution of S-polysaccharides (d) Banding pattern within the mineral phase. Correspondence between mineral stepping growth and layered distribution of polysaccharides indicates that the two phases (organic and mineral) interplay at a submicrometre scale.

Figure 22. (left) X-ray fluorescence maps of a Pu-doped piece of Yucca Mountain tuff. Shown are the intensities of the fluorescence Unes for Mn and Pu in the region of a Mn-rich mineral phase. Each map is 150 x 150 pm, and was made with 5 pm step sizes (adapted from Newville et al. 1999). 

The coordination of copper in vapor phase inclusions coexisting with brine from the Mole Granite, NSW, Australia has been studied (Mavrogenes et al. 2002). X-ray fluorescence maps indicate that copper is concentrated in the vapor inclusions and at room temperature uniformly distributed in the condensed fluid. Opaque precipitates in these inclusions do not contain copper. Through a comparison with XAFS spectra on known copper compounds at temperatures up to 325°C (Fulton et al. 2000), the... 

Figure 4. (A) Electron micrograph of fracture surface from an x = 0.1S8 pellet produced by composite method. The distance between the black dots on the white bar corresponds to 10 /im. (B) X-ray fluorescence map of bismuth for the same region as in (A). White points indicate th presence of detected element. Continued on next page.

While three-dimensional imaging is likely to have the most dramatic impact, there are opportunities to carry out fast radiography to image two-dimensional processes in thin foils at submillisecond rates. Such imaging can also be correlated with chemical information, including X-ray fluorescence maps. X-ray absorption spectroscopy, microdifffaction, and small-angle scattering. The spatial distribution of different chemical species is important for the development of robust corrosion... 

Figure 10.10 X-ray fluorescence maps of P, S, Cl, K, and Cs from isolated Arabi-dopsis thaliana cells grown in presence of (A) 20 mM K, OmM Cs (B) 20 mM K, 1 mM Cs, and (C) 0 mM K, 1 mM Cs and photonic images of control cells prepared as thin section (D) and in vivo (E). Relative intensities, given by the scale bar, were normalized relative to the incident beam intensity recorded on each point. The incident X-ray energy was 5.8 keV and the beam size was H = 0.7 pm x V = 0.4 pm. For (A), scale bar=15pm, step size = 0.5pm, dwell time = 0.5spoint . For (B), scale bar = 22 pm, step size = 0.7 pm, dwell time = 0.5 s point . For (C), scale bar = 20 pm, step size = 0.5 pm, dwell time = 0.5 s point 2006 Elsevier Masson SAS...

Abstract Mobile Au in soil has been postulated for many years. It has been used by the mineral exploration industry in areas of transported overburden as a vector towards buried deposits. Until now, the nature of this mobile Au has not been known or investigated. Soil samples from a colluvial area above the Bounty Deposit (Yilgarn Craton, Western Australia) investigated by analytical techniques including laser ablation inductively coupled mass spectrometry (LA-ICP-MS) and synchrotron x-ray fluorescence (SXRF) combined with X-ray absorption spectrometry (XAS) have allowed us to map the invisible Au in these soils and suggests that at least some of it occurs in an ionic form. 

In a similar manner to SAXS, microfocus X-ray fluorescence analysis can be targeted at small spot sizes and this can be linked to visual analysis of the archaeological thin-section. Figure S shows an example from the Kongshavn archaeological site in Finnmark, Norway (33). Here maps of elemental distributions (Figure Sb, Sc) can be linked visually to the assemblage materials... 

To verify the success of the different deposition steps, in combination with the Split Pool methodology X-ray fluorescence was chosen as an analysis tool. Elemental analysis was performed by X-ray fluorescence analysis on an Eagle II pProbe (Roentgenanalytik) with Rh-Ka radiation. An essential feature is the small diameter of the measurement spot The X-ray beam is focused by a multi-capillary system to a 50 pm spot on the sample surface. XRF analysis of the 8x12 catalyst library selection (Fig. 2.20) was routinely accomplished automatically by an elemental mapping at a pattern of 512x400 points, equally distributed over the rectangular library field, each point (50 pm diameter) was measured for 300 ms. 

Overall, our results suggest that solvent extraction has little impact on the Tin (IV) species, implying a phase that has strong interactions with the polymer network. In contrast, the Tin (II) species appears to be partially extractable, suggesting a more mobile component. To further assess the mobility and to map the tin distribution, we have used X-ray fluorescence studies. Figure 3 shows the... 

Stohr J, Noguera C, Kendelewicz T (1984) Auger and photoelectron contributions to the electron-yield surface extended X-ray-absorption fine-structure signal. Phys Rev 630 5571-5579 Sutton SR, Bajt S, Delaney J, Schulze D, Tokunaga T (1995) Synchrotron X-ray fluorescence microprobe Quantification and mapping of mixed valence state samples using micro-XANES. Rev Sci Instrum 66 1464-1467... 

Another example of the utility of mapping the spatial distribution of trace elements and their association with other elements or phases comes from a recent X-ray fluorescence microtomography study of the spatial distribution of Pb, Fe, Mn, Zn, and As on and within the roots of Phalaris arundinacea, a common aquatic plant from a mine waste impacted wetland in the Coeur d Alene Basin of northern Idaho (Hansel et al. 

Figure 9. Side views of the sample regions of the experimental setups used on station 7.3.3 at the ALS for combined X-ray fluorescence and diffraction in transmission and reflection mode. The white wedge to the left of each frame represents the focused beam (width not to scale) coming from the vertical-focus mirror on the left. The large black object is the diffraction detector. The cylindrical object coming in from the upper left is the Si detector used for fluorescence mapping.

Figure 31. a) X-ray fluorescence spectra and two-dimensional pXRD patterns (A = 1.968 A) from four selected points-of-interest for the nodule presented in Figure 30. b) pSXRD (negative contrast) maps of lithiophorite and goethite. c) One-dimensional pXRD patterns obtained by integrating intensities of 2D patterns at constant Bragg angle. ... 

For numerous questions related to the speciation of metal(loid) contaminants in natural and waste matrices, the combination of X-ray fluorescence, diffraction and absorption presented in this chapter offers a unique access to the problem. X-ray microscopy cannot compete with the atomic resolution offered by electron microscopy, but it offers a number of unique features. The chemical and structural information obtained by pSXRF and pSXRD can be used to identify the host solid phase by mapping the distributions of elements and solid species, respectively. Then the molecular-scale binding mechanism of trace elements by the host phase can be unraveled by pEXAFS spectroscopy. All these techniques can be applied with minimum preparation, minimizing any possible alteration of the sample. However, caution should be taken to not modify the initial form of the metal species by photon-assisted oxidation or reduction. This problem can be circumvented by decreasing the exposure time, photon density, or temperature. The polarization of the synchrotron radiation can be used to analyze anisotropic materials, which is important since many environmental minerals have a layered structure. 

Oxidation state maps can be produced for samples containing an element in multiple states (Sutton et al. 1995). The basic approach in oxidation state mapping is to make multiple, 2-dimensional X-ray fluorescence (elemental) maps of the specimen using monochromatic radiation where the monochromatic energy for each map is chosen to... 

Tokunaga T, Sutton SR, Bajt S (1994) Mapping of selenium concentrations in soil aggregates with synchrotron X-ray fluorescence microprobe. Soil Science 158 421-433... 

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