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“Trace analysis of estuarine brown algae by energy-dispersive X-ray fluorescence”. Sauter L, Van der Ben D, Van Grieken R, X-ray spectrometry 8, 159 (1979). http://doi.org/10.1002/XRS.1300080405
Abstract: Brown algae, which are good indicators for estuarine metal pollution, can advantageously be analysed by energy-dispersive X-ray fluorescence. The use of thin film samples and samples of intermediate thickness has several advantages over the conventional thick pellet procedure. A quite homogeneous thin target is prepared by suspending 15 mg of dried and ground seaweed powder in bi-distilled water and evaporating the slurry on a 10 cm2 Mylar foil held in a Teflon ring. The effective sample weight in the beam is calculated by a procedure based on the scatter peaks in the spectrum. Sensitivities are typically in the 215 ppm range. The coefficient of variation per analysis averaged over ten elements amounts to 10%. The natural concentration variation in seaweed specimens at one location is 13%. Samples from locations in the more polluted western Scheldt estuary yield significantly higher values for several elements, relative to the eastern Scheldt sites. Possible trace element variations between the top and base of plants, and between different seaweed specimens and sampling seasons, are discussed.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300080405
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“Folding of aerosol loaded filters during X-ray fluorescence analysis”. Van Grieken RE, Adams FC, X-ray spectrometry 5, 61 (1976). http://doi.org/10.1002/XRS.1300050204
Abstract: Folding aerosol loaded filters in two with the loaded side inwards during the X-ray analysis not only reduces possible filter heterogeneity effects and improves sample protection, but also increases the sensitivity and renders filter paper absorption corrections simple and more accurate in many instances. It is shown that folding an aerosol loaded Whatman filter paper during Kα X-rays counting leads to an increased sensitivity for all elements up from calcium, scandium or titanium (depending on the sensitivity definition and on the aerosol load) and for all elements up from phosphorus, sulphur or chlorine in the case of the Nuclepore filter. Although the absorption by the filter, into which the aerosol penetrates to some extent, is always more important in the sandwich than in the usual geometry, the dependence of the absorption correction on the usually unknown average deposition depth is less pronounced. Assuming all the aerosol material to be collected at the very surface of the filter and hence being present in the centre of the sandwich to be analysed, leads to an extremely simple filter paper absorption correction which is less prone to uncertainties than more sophisticated corrections in the usual geometry requiring additional measurements. This is the case for all elements up from potassium on Whatman filters and up from phosphorus on Nuclepore filters.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300050204
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“Awards for best referees of X-ray Spectrometry”. Van Grieken R, X-ray spectrometry 43, 68 (2014). http://doi.org/10.1002/XRS.2530
Keywords: Editorial; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2530
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“Introducing John Campbell, the new regional editor for North America of X-Ray Spectrometry”. Van Grieken R, X-ray spectrometry 43, 67 (2014). http://doi.org/10.1002/XRS.2534
Keywords: Editorial; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2534
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“Evaluation of an equation for bremsstrahlung background in electron-probe X-ray microanalysis of composite samples”. Markowicz A, Storms H, Van Grieken R, X-ray spectrometry 15, 131 (1986). http://doi.org/10.1002/XRS.1300150211
Abstract: A new equation for predicting the generated bremsstrahlung background intensity in electron-probe x-ray microanalysis has been verified experimentally. This equation is applicable to all bulk composite specimens and reduces to Kramers' equation for pure elements only. The experimental verification has been carried out for Al2O3, Fe2O3 and ZrO2 with radiation energies from 4.2 to 14.8 keV. The predicted bremsstrahlung intensities are in good agreement with the experimental data.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300150211
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“A simple absorption correction for electron probe X-ray microanalysis of bulk samples”. Markowicz A, Storms H, Van Grieken R, X-ray spectrometry 15, 115 (1986). http://doi.org/10.1002/XRS.1300150209
Abstract: A simple procedure is proposed for the calculation of the absorption correction factor in electron-probe x-ray microanalysis. It is based on the concept of an effective depth of x-ray production, assuming a rectangular depth distribution function for x-ray generation. This effective x-ray production depth is expressed as a fraction of the x-ray excitation depth given by Whelan's expression. Adequate values for this fraction are presented. Two versions are considered. In the first the effective x-ray production is a function of both the characteristic x-ray energy and the atomic numbers of the matrix elements, whereas in the second one, which is indicated for routine use, the energy dependence is neglected. Calculations pointed to satisfactory results, even for low x-ray energies and high overvoltages.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300150209
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“Monte Carlo simulation of backscattered peaks in secondary target energy-dispersive X-ray spectra”. Van Dyck P, Török S, Van Grieken R, X-ray spectrometry 15, 231 (1986). http://doi.org/10.1002/XRS.1300150403
Abstract: A Monte Carlo simulation has been developed to describe the incoherent and coherent scatter processes for the complex geometry of a secondary target energy-dispersive x-ray fluorescence system. Photons are followed from the x-ray tube anode until the detection of scattered secondary target photons in the active Si layer of the detector. The program quantitatively shows the broadening of the incoherent scatter peak with increasing atomic number, and it models the incoherent peak shape adequately. The incoherent-to-coherent scatter intensity ratios obtained differ by 1030% from the theoretical values, while their dependence on the sample atomic number corresponds to that expected from theory.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300150403
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“Semi-quantitative analysis of the formation of a calcium oxalate protective layer for monumental limestone using combined micro-XRF and micro-XRPD”. Vanmeert F, Mudronja D, Fazinic S, Janssens K, Tibljas D, X-ray spectrometry 42, 256 (2013). http://doi.org/10.1002/XRS.2486
Abstract: A current method for the protection of cretaceous limestone present in various monuments consists of performing a passivating treatment with ammonium oxalate (AmOx). A calcium oxalate protective layer is formed on the surface and enhances the acid resistance of the stone. The in-depth formation of the calcium oxalate layer was investigated on cross sections by using combined micro X-ray fluorescence and micro X-ray powder diffraction (mu XRF/mu XRPD). XRPD showed the presence of both whewellite and weddellite in the calcite stone matrix. A correction was made for sample misalignment, which was visible in both the fluorescence and the diffraction line measurements. A semi-quantitative analysis was performed on the basis of Klug's equation for a two-phase mixture (the presence of weddellite was neglected) without the need for a known reference sample. By assuming two extreme compositions for a reference weight fraction (1 and 99wt%), it was possible to obtain whewellite concentration profiles, which can be used for comparing the effectiveness of different methods for the application of AmOx to the stone surface and the effect of treatment time and AmOx concentration used. It is shown that for the relative amounts of whewellite formed, the differences due to the assumed weight fractions are smaller than the errors due to sample heterogeneity and preferred orientation. Copyright (c) 2013 John Wiley & Sons, Ltd.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.298
Times cited: 5
DOI: 10.1002/XRS.2486
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“Editorial : introducing Dr Markowicz as X-Ray Spectrometry's new associate editor for Europe”. Van Grieken R, X-ray spectrometry 42, 175 (2013). http://doi.org/10.1002/XRS.2447
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2447
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“Editorial : award for best X-Ray Spectrometry referee during 2011-2012”. Van Grieken R, X-ray spectrometry 42, 3 (2013). http://doi.org/10.1002/XRS.2428
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2428
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“New members of the editorial board of X-ray Spectrometry”. Van Grieken R, X-ray spectrometry 42, 1 (2013). http://doi.org/10.1002/XRS.2431
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2431
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