skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The ISAS Synchrotron Microprobe at DELTA

Abstract

Since 2004 ISAS operates a dipole beamline at the synchrotron radiation facility DELTA at University of Dortmund. Synchrotron radiation is used at this beamline as an excellent excitation source for X-ray fluorescence spectrometry (XRF). Among others, the high brilliance of the synchrotron radiation in contrast to conventional X-ray tubes, the strong polarization of the synchrotron radiation and the low divergence of the electron beam can be applied to XRF offering several advantages for spectroscopy. These outstanding features encouraged us to develop and operate a synchrotron radiation induced X-ray micro fluorescence probe connected to a wavelength dispersive spectrometer (SR-WDXRF). A relevant characteristic of such a device, namely, good lateral resolution at high spectral resolution can be applied for single spot-, line-scan and area map analyses of a variety of objects. The instrumentation of the SR-WDXRF and the performed experiments will be presented. Main task is the detection of light elements by their fluorescence K-lines and the specification of element compounds.

Authors:
; ;  [1];  [2]
  1. ISAS Institute for Analytical Sciences, Bunsen-Kichhoff-Strasse 11, 44139 Dortmund (Germany)
  2. DELTA Institut fuer Beschleunigerphysik und Synchrotronstrahlung, Maria-Goeppert-Mayer-Strasse 2, 44221 Dortmund (Germany)
Publication Date:
OSTI Identifier:
21052652
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436194; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BEAM PRODUCTION; DIPOLES; ELECTRON BEAMS; EXCITATION; FLUORESCENCE SPECTROSCOPY; PHOTON BEAMS; POLARIZATION; PROBES; RESOLUTION; SPECIFICATIONS; SYNCHROTRON RADIATION; SYNCHROTRON RADIATION SOURCES; WAVELENGTHS; X RADIATION; X-RAY FLUORESCENCE ANALYSIS; X-RAY TUBES

Citation Formats

Bohlen, Alex von, Kraemer, Markus, Hergenroeder, Roland, and Berges, Ulf. The ISAS Synchrotron Microprobe at DELTA. United States: N. p., 2007. Web. doi:10.1063/1.2436194.
Bohlen, Alex von, Kraemer, Markus, Hergenroeder, Roland, & Berges, Ulf. The ISAS Synchrotron Microprobe at DELTA. United States. doi:10.1063/1.2436194.
Bohlen, Alex von, Kraemer, Markus, Hergenroeder, Roland, and Berges, Ulf. 2007. "The ISAS Synchrotron Microprobe at DELTA". United States. doi:10.1063/1.2436194.
@article{osti_21052652,
title = {The ISAS Synchrotron Microprobe at DELTA},
author = {Bohlen, Alex von and Kraemer, Markus and Hergenroeder, Roland and Berges, Ulf},
abstractNote = {Since 2004 ISAS operates a dipole beamline at the synchrotron radiation facility DELTA at University of Dortmund. Synchrotron radiation is used at this beamline as an excellent excitation source for X-ray fluorescence spectrometry (XRF). Among others, the high brilliance of the synchrotron radiation in contrast to conventional X-ray tubes, the strong polarization of the synchrotron radiation and the low divergence of the electron beam can be applied to XRF offering several advantages for spectroscopy. These outstanding features encouraged us to develop and operate a synchrotron radiation induced X-ray micro fluorescence probe connected to a wavelength dispersive spectrometer (SR-WDXRF). A relevant characteristic of such a device, namely, good lateral resolution at high spectral resolution can be applied for single spot-, line-scan and area map analyses of a variety of objects. The instrumentation of the SR-WDXRF and the performed experiments will be presented. Main task is the detection of light elements by their fluorescence K-lines and the specification of element compounds.},
doi = {10.1063/1.2436194},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = 2007,
month = 1
}
  • We have augmented and reanalyzed the Spinrad-Taylor scanner data for M31 in order to see whether any stellar mix can reproduce both these data and observed CO and Wing-Ford band indices. We have also tried to clarify the status of the anomalous strengths (''ISAa'') of certain spectral features which Spinrad and Taylor found; a reanalysis published by Faber had left their status uncertain. Our reanalysis yields the following conclusions:1. The Spinrad-Taylor data display large strength excesses in the b triplet and D lines, smaller strength excesses in a red CN band and some TiO bands, and marginal or definite strengthmore » deficiencies in the G band, the blue CN band, Ca I lambda4227, and Fe I lambda4384. Low microturbulence (compared to solar-neighborhood stars) may account for the strength deficiencies. Both excesses and deficiencies can inflate a model's summed squared residuals, and large excesses can bias the operation of model-building algorithms.2. There is no clearly satisfactory way to account simultaneously for the CO and Wing-Ford bands and Spinrad and Taylor's lambda8190 index. Moreover, no model quite reproduces Spinrad and Taylor's 1 ..mu..m colors. This problem also appears: but not decisively: in data published by O'Connell.3. Spinrad and Taylor's conclusions were influenced by certain key assumptions which have since been improved, or which can now be shown to be incorrect.4. The combined data of Wood and McClure and van den Bergh do not require strong CN stars to reproduce them, and thus are not necessarily in conflict with Spinrad and Taylor's data.« less
  • 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.
  • We have been developing an instrument that combines the techniques of x-ray photoelectron spectroscopy and zone plate microfocusing to perform spectromicroscopy. The X1A undulator provides a bright photon source in the soft x-ray range with a high degree of spatial coherence (a requirement for zone plate focusing). A spherical grating monochromator selects the desired photon energy in the 280--800 eV range. A Fresnel zone plate focuses the beam to a small spot. Photoelectron spectra can be acquired from the small irradiated area with an electron energy analyzer. With the beam focused on the surface and the sample mechanically scanned, element-specificmore » or chemical-state-specific images of the surface can be obtained.« less
  • The possible occurrence of reducing microsites in synthetic soil aggregates and their influences on the distribution of selenium species with redox-dependent mobilities was tested using the synchrotron X-ray fluorescence microprobe (SXRFM). Synthetic, effectively two-dimensional soil aggregates of diameters ranging from 10 to 30 mm were constructed, with and without inclusion of sections of Scirpus robustus and S. californicus root sections. Each aggregate was uniformly wetted with a saline solution containing 240 g m{sup {minus}3} Se [98% as Se(VI), and 2% as Se(IV)]. Gas-phase porosities varied between individual aggregates from 0.00 to 0.40 and were maintained relatively constant during the incubationmore » period of up to 17 days. Exchanges of soil gases with atmospheric air occurred only along the periphery of the aggregates. Scanning of the aggregates using SXRFM demonstrated that Se was essentially homogeneously distributed in soils without Scirpus root sections, suggesting that Se remained primarily as the soluble Se(VI) species. The SXRFM results revealed large accumulations of total Se was measured in water-saturated soils within 1 to 4 mm of decomposing roots. These observations provide support for a model of localized reducing zones in which Se(VI) is reduced to less mobile Se(IV) and to insoluble Se(0), resulting in local accumulation of total Se. The measured Se accumulation in one microsite compared reasonably well with a simple transient Se(VI) diffusion model. It is postulated that such mechanism may account for similar heterogeneities observable in some Se-contaminated soils at Kesterson Reservoir. Such heterogeneities in concentrations of Se and other constituents within individual soil aggregates have important implications with respect to reactivity and need to be included in any detailed mechanistic modeling of chemical cycling within soils. This work provides an example of the substantial capabilities of SXRFM in studies of soils. 45 refs., 11 figs.« less
  • A synchrotron X-ray fluorescence microprobe has been used to study the composition and microstructure of pulsed-laser ablation-deposited films of calcium-nickel-potassium oxides that have applications in heterogeneous catalysis. The films, whose individual metal oxide components have widely varying boiling points and thus prevent a solid-phase synthesis with the use of standard thermal techniques, represent a new quaternary metal oxide phase containing the three elements. Experimental conditions for preparing the films are given. The X-ray fluorescence microprobe data are discussed with respect to both the distribution of the three metals in the films at the micrometer lateral spatial resolution level and themore » presence of trace amounts of metals that were introduced into the films as contaminants in targets made of the parent three-metal oxide. {copyright} {ital 1997} {ital Society for Applied Spectroscopy}« less