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Author |
Labrecque, J.J.; Beusen, J.M.; Van Grieken, R.E. |
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Title |
Determination of barium, lanthanum, cerium and neodymium in lateritic materials by various energy-dispersive X-ray fluorescence techniques and neutron activation analysis |
Type |
A1 Journal article |
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Year |
1986 |
Publication  |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
1 |
Pages |
13-18 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A comparison of four methods for the determination of barium, lanthanum, cerium and neodymium in lateritic materials from Brazil is presented. Three of the methods were based on x-ray fluorescence (XRF) spectroscopy: two by radioisotope excitation (Co-57 and Am-241) and one by secondary target XRF (a molybdenum target with a tungsten anode). The other method was based on neutron activation analysis employing both a Ge(Li) coaxial detector and a high-purity germanium detector. The results from these four methods were similar for lanthanum, cerium and neodymium, but for barium at low concentrations (<500 ppm) the neutron activation and the secondary target XRF methods were not suitable. Data on the precision and accuracy of these methods using a series of standard reference rocks are given. The advantages and limitations of each of these methods with respect to the analysis of lateritic materials are discussed. |
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Wos |
A1986AYN6000003 |
Publication Date |
2005-05-28 |
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ISSN |
0049-8246 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:116487 |
Serial |
7774 |
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Author |
Markowicz, A.; Storms, H.; Van Grieken, R. |
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Title |
Evaluation of an equation for bremsstrahlung background in electron-probe X-ray microanalysis of composite samples |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
2 |
Pages |
131-133 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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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. |
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Wos |
A1986C017300009 |
Publication Date |
2005-05-28 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:113873 |
Serial |
7937 |
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Author |
Török, S.; Braun, T.; Van Dyck, P.; Van Grieken, R. |
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Title |
Heterogeneity effects in direct XRF analysis of traces of heavy metals preconcentrated on polyurethane foam sorbents |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
1 |
Pages |
7-11 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Trace amounts of heavy metals were preconcentrated on discs of polyurethane (PU) foam loaded with ammonium diethyldithiocarbamate (DDTC), to increase the sensitivity of XRF. Since the diameter of the cavities in the open-cell PU foams reaches 30300 μm, considerable heterogeneity effects might occur, which could reduce the accuracy of the method. The possible systematic error introduced by considering the sample to be homogeneous is calculated using the Berry et al. model. The calculations show that the underestimation of the absorption correction factor when considering the sample as being homogeneous is less than 2% for high-Z elements when the sample thickness is at least 2 mm. The detection limits are also around the minima for this thickness. |
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Wos |
A1986AYN6000002 |
Publication Date |
2005-05-28 |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116488 |
Serial |
8030 |
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Author |
Van Dyck, P.; Török, S.; Van Grieken, R. |
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Title |
Monte Carlo simulation of backscattered peaks in secondary target energy-dispersive X-ray spectra |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
4 |
Pages |
231-238 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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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. |
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A1986E535600001 |
Publication Date |
2005-05-28 |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:113612 |
Serial |
8280 |
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Author |
Markowicz, A.; Storms, H.; Van Grieken, R. |
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Title |
A simple absorption correction for electron probe X-ray microanalysis of bulk samples |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
2 |
Pages |
115-119 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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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. |
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Wos |
A1986C017300007 |
Publication Date |
2005-05-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:113872 |
Serial |
8524 |
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