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	Author	Terzano, R.; al Chami, Z.; Vekemans, B.; Janssens, K.; Miano, T.; Ruggiero, P.
	Title	Zinc distribution and speciation within rocket plants (Eruca vesicaria L. Cavalieri) grown on a polluted soil amended with compost as determined by XRF microtomography and Micro-Xanes			Type	A1 Journal article
	Year	2008	Publication	Journal of agricultural and food chemistry	Abbreviated Journal	J Agr Food Chem
	Volume	56	Issue	9	Pages	3222-3231
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000255655600050	Publication Date	2008-04-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8561	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.154	Times cited	68	Open Access
	Notes				Approved	Most recent IF: 3.154; 2008 IF: 2.562
	Call Number	UA @ admin @ c:irua:69147			Serial	5925
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	Author	Šmit, Ž.; Janssens, K.; Proost, K.; Langus, I.
	Title	Confocal μ-XRF depth analysis of paint layers			Type	A1 Journal article
	Year	2004	Publication	Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms	Abbreviated Journal	Nucl Instrum Meth B
	Volume	219	Issue		Pages	35-40
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Focused narrow-band beam of the synchrotron radiation was used for in-depth analysis of historic and modern paint layers. The fluorescent radiation induced by 21 keV impact radiation was detected by a Si(Li) detector equipped with a polycapillary X-ray lens in con-focal geometry. Scanning of the sample was performed by a motorized xyz stage. Space resolution of 30 ìm was achieved. The procedure of evaluation of concentrations was based on the independent parameter method and included absorption of radiation in the outer layers and secondary fluorescence enhancement induced by hard X-rays of the same and neighboring layers.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000221895800009	Publication Date	2004-02-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0168-583x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.109	Times cited	69	Open Access
	Notes				Approved	Most recent IF: 1.109; 2004 IF: 0.997
	Call Number	UA @ admin @ c:irua:71386			Serial	5552
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	Author	de Nolf, W.; Janssens, K.
	Title	Micro X-ray diffraction and fluorescence tomography for the study of multilayered automotive paints			Type	A1 Journal article
	Year	2010	Publication	Surface and interface analysis	Abbreviated Journal	Surf Interface Anal
	Volume	42	Issue	5	Pages	411-418
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Combined microscopic X-ray fluorescence/microscopic X-ray diffraction (µ-XRF/µ-XRD) tomography is a recently developed method that allows the visualization of the distribution of chemical elements and the associated crystalline phases inside complex, heterogeneous materials of extended thickness (millimeter range) in a nondestructive fashion. In this paper, the accuracy and resolution with which the individual layers in a multilayer stack of automotive paints can be distinguished is evaluated, and some of their properties measured. A paint layer system of eight layers was investigated, in which eight different crystalline substances were identified, each layer consisting of an organic, synthetic resin doped with finely milled inorganic compounds that serve as pigments or to strengthen the layer. In the XRD tomograms, all paint layers could be straightforwardly distinguished and their average thickness calculated. In case the filtered back projection method was used for tomogram reconstruction, a spatial resolution comparable to the microbeam size was obtained indicating no significant reconstruction blurring. When a more robust reconstruction method, such as the maximum-likelihood expectation maximization method, was employed, tomograms showing fewer artifacts were obtained, but with a spatial resolution that was two times worse. In the corresponding XRF tomograms, significant self-absorption distorted the element-specific tomograms corresponding to the low-energy (<7 keV) characteristic radiation and limited their usefulness. It can be concluded that microbeam XRD tomography allows the accurate visualization of the distribution of crystalline phases in multilayered automotive paint materials of millimeter dimensions with sufficient resolution to allow separate characterization of each layer in terms of its crystal-phase composition and thickness.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000277350900012	Publication Date	2009-11-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0142-2421	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.132	Times cited	70	Open Access
	Notes	; This research was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16) and funded by beam time grants from HASYLAB. This paper also presents results from a GOA project of the Research Fund of the University of Antwerp (Belgium), and of FWO (Brussels, Belgium) project nos. G.0177.03, G.0103.04, and G.0689.06. We also would like to acknowledge the Institute of Forensic Research in Krakow, Poland, and in particular Dr J. Zieba for providing the paint layer sample. ;			Approved	Most recent IF: 1.132; 2010 IF: 1.249
	Call Number	UA @ admin @ c:irua:82764			Serial	5717
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	Author	Tadić, M.; Peeters, F.M.; Janssens, K.L.
	Title	Effect of isotropic versus anisotropic elasticity on the electronic structure of cylindrical InP/In_0.49Ga_0.51P self-assembled quantum dots			Type	A1 Journal article
	Year	2002	Publication	Physical review : B : condensed matter and materials physics	Abbreviated Journal	Phys Rev B
	Volume	65	Issue	16	Pages	165333-13
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The electronic structure of disk-shaped InP/InGaP self-assembled quantum dots is calculated within the effective-mass theory. The strain-dependent 6x6 multiband Hamiltonian for the valence band is simplified into an axially symmetric form. Both the continuum mechanical model, discretized by finite elements, and the isotropic model are used to calculate the strain distribution and their results are critically compared. The dependence of the electron and the hole energy levels on the dimensions of the quantum dot is investigated. We found that both the electron and hole energies are underestimated if the strain distribution is calculated by the isotropic elasticity theory. The agreement between the electron energies for the two approaches is better for thinner quantum dots. The heavy holes are confined inside the quantum dot, while the light holes are located outside the disk, but confined by the strain field near the edge of the disk periphery. We found that the (h) over bar /2 hole ground state crosses the 3 (h) over bar /2 ground state when the height of the quantum dot increases and becomes the ground state for sufficiently thick quantum disks. The higher hole levels exhibit both crossings between the states of the different parity and anticrossings between the states of the same parity.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000175325000097	Publication Date	2002-07-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0163-1829;1095-3795;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	72	Open Access
	Notes				Approved	Most recent IF: 3.836; 2002 IF: NA
	Call Number	UA @ lucian @ c:irua:103361			Serial	819
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	Author	Tadić, M.; Peeters, F.M.; Janssens, K.L.; Korkusinski, M.; Hawrylak, P.
	Title	Strain and band edges in single and coupled cylindrical InAs/GaAs and InP/InGaP self-assembled quantum dots			Type	A1 Journal article
	Year	2002	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	92	Issue	10	Pages	5819-5829
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A comparative study is made of the strain distribution in cylindrical InAs/GaAs and InP/InGaP self-assembled quantum dots as obtained from isotropic elasticity theory, the anisotropic continuum mechanical model, and from atomistic calculations. For the isotropic case, the recently proposed approach [J. H. Davies, J. Appl. Phys. 84, 1358 (1998)] is used, while the finite-element method, the valence force field method, and Stillinger-Weber potentials are employed to calculate the strain in anisotropic structures. We found that all four methods result in strain distributions of similar shapes, but with notable quantitative differences inside the dot and near the disk-matrix boundary. The variations of the diagonal strains with the height of the quantum dot, with fixed radius, as calculated from all models, are almost linear. Furthermore, the energies of the band edges in the two types of quantum dots are extracted from the multiband effective-mass theory by inserting the strain distributions as obtained by the four models. We demonstrated that all strain models produce effective potentials for the heavy and light holes which agree very well inside the dot. A negligible anisotropy of all normal strains in the (x,y) plane is found, which, providing the axial symmetry of the kinetic part of the multiband effective-mass Hamiltonian, justifies the use of the axial approximation. Strain propagation along the vertical direction is also considered with the aim to study the influence of strain on the electron coupling in stacks of quantum dots. We found that the interaction between the strain fields of the individual quantum dots makes the effective quantum wells for the electrons in the conduction band shallower, thereby counteracting the quantum mechanical coupling. (C) 2002 American Institute of Physics.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000178987200036	Publication Date	2002-11-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.068	Times cited	73	Open Access
	Notes				Approved	Most recent IF: 2.068; 2002 IF: 2.281
	Call Number	UA @ lucian @ c:irua:103327			Serial	3164
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	Author	Cotte, M.; Susini, J.; Dik, J.; Janssens, K.
	Title	Synchrotron-based X-ray absorption spectroscopy for art conservation: looking back and looking forward			Type	A1 Journal article
	Year	2010	Publication	Accounts of chemical research	Abbreviated Journal	Accounts Chem Res
	Volume	43	Issue	6	Pages	705-714
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	A variety of analytical techniques augmented by the use of synchrotron radiation (SR), such as X-ray fluorescence (SR-XRF) and X-ray diffraction (SR-XRD), are now readily available, and they differ little, conceptually, from their common laboratory counterparts. Because of numerous advantages afforded by SR-based techniques over benchtop versions, however, SR methods have become popular with archaeologists, art historians, curators, and other researchers in the field of cultural heritage (CH). Although the CH community now commonly uses both SR-XRF and SR-XRD, the use of synchrotron-based X-ray absorption spectroscopy (SR-XAS) techniques remains marginal, mostly because CH specialists rarely interact with SR physicists. In this Account, we examine the basic principles and capabilities of XAS techniques in art preservation. XAS techniques offer a combination of features particularly well-suited for the chemical analysis of works of art. The methods are noninvasive, have low detection limits, afford high lateral resolution, and provide exceptional chemical sensitivity. These characteristics are highly desirable for the chemical characterization of precious, heterogeneous, and complex materials. In particular, the chemical mapping capability, with high spatial resolution that provides information about local composition and chemical states, even for trace elements, is a unique asset. The chemistry involved in both the objects history (that is, during fabrication) and future (that is, during preservation and restoration treatments) can be addressed by XAS. On the one hand, many studies seek to explain optical effects occurring in historical glasses or ceramics by probing the molecular environment of relevant chromophores. Hence, XAS can provide insight into craft skills that were mastered years, decades, or centuries ago but were lost over the course of time. On the other hand, XAS can also be used to characterize unwanted reactions, which are then considered alteration phenomena and can dramatically alter the objects original visual properties. In such cases, the bulk elemental composition is usually unchanged. Hence, monitoring oxidation state (or, more generally, other chemical modifications) can be of great importance. Recent applications of XAS in art conservation are reviewed and new trends are discussed, highlighting the value (and future possibilities) of XAS, which remains, given its potential, underutilized in the CH community.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000278842500003	Publication Date	2010-01-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0001-4842	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	20.268	Times cited	74	Open Access
	Notes	; ;			Approved	Most recent IF: 20.268; 2010 IF: 21.852
	Call Number	UA @ admin @ c:irua:83982			Serial	5861
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	Author	Somogyi, A.; Drakopoulos, M.; Vincze, L.; Vekemans, B.; Camerani, C.; Janssens, K.; Snigirev, A.; Adams, F.
	Title	ID18F: a new micro-X-ray fluorescence end-station at the European Synchrotron Radiation Facility (ESRF): preliminary results			Type	A1 Journal article
	Year	2001	Publication	X-ray spectrometry	Abbreviated Journal	X-Ray Spectrom
	Volume	30	Issue		Pages	242-252
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000170089700006	Publication Date	2002-09-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0049-8246	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.298	Times cited	76	Open Access
	Notes				Approved	Most recent IF: 1.298; 2001 IF: 1.414
	Call Number	UA @ admin @ c:irua:34062			Serial	5647
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	Author	Janssens, K.; Dik, J.; Cotte, M.; Susini, J.
	Title	Photon-based techniques for nondestructive subsurface analysis of painted cultural heritage artifacts			Type	A1 Journal article
	Year	2010	Publication	Accounts of chemical research	Abbreviated Journal	Accounts Chem Res
	Volume	43	Issue	6	Pages	814-825
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Often, just micrometers below a paintings surface lies a wealth of information, both with Old Masters such as Peter Paul Rubens and Rembrandt van Rijn and with more recent artists of great renown such as Vincent Van Gogh and James Ensor. Subsurface layers may include underdrawing, underpainting, and alterations, and in a growing number of cases conservators have discovered abandoned compositions on paintings, illustrating artists practice of reusing a canvas or panel. The standard methods for studying the inner structure of cultural heritage (CH) artifacts are infrared reflectography and X-ray radiography, techniques that are optionally complemented with the microscopic analysis of cross-sectioned samples. These methods have limitations, but recently, a number of fundamentally new approaches for fully imaging the buildup of hidden paint layers and other complex three-dimensional (3D) substructures have been put into practice. In this Account, we discuss these developments and their recent practical application with CH artifacts. We begin with a tabular summary of 14 IR- and X-ray-based imaging methods and then continue with a discussion of each technique, illustrating CH applications with specific case studies. X-ray-based tomographic and laminographic techniques can be used to generate 3D renditions of artifacts of varying dimensions. These methods are proving invaluable for exploring inner structures, identifying the conservation state, and postulating the original manufacturing technology of metallic and other sculptures. In the analysis of paint layers, terahertz time-domain spectroscopy (THz-TDS) can highlight interfaces between layers in a stratigraphic buildup, whereas macrosopic scanning X-ray fluorescence (MA-XRF) has been employed to measure the distribution of pigments within these layers. This combination of innovative methods provides topographic and color information about the micrometer depth scale, allowing us to look into paintings in an entirely new manner. Over the past five years, several new variants of traditional IR- and X-ray-based imaging methods have been implemented by conservators and museums, and the first reports have begun to emerge in the primary research literature. Applying these state-of-the-art techniques in a complementary fashion affords a more comprehensive view of paintings and other artworks.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000278842500013	Publication Date	2010-05-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0001-4842	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	20.268	Times cited	78	Open Access
	Notes	; This research was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of FWO (Brussels, Belgium) projects nr. G.0704.08 and G.0179.09 and from the UA-BOF GOA programme. ;			Approved	Most recent IF: 20.268; 2010 IF: 21.852
	Call Number	UA @ admin @ c:irua:83983			Serial	5772
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	Author	Monico, L.; Janssens, K.; Miliani, C.; Brunetti, B.G.; Vagnini, M.; Vanmeert, F.; Falkenberg, G.; Abakumov, A.; Lu, Y.; Tian, H.; Verbeeck, J.; Radepont, M.; Cotte, M.; Hendriks, E.; Geldof, M.; van der Loeff, L.; Salvant, J.; Menu, M.;
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 3 : synthesis, characterization, and detection of different crystal forms of the chrome yellow pigment			Type	A1 Journal article
	Year	2013	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	85	Issue	2	Pages	860-867
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The painter, Vincent van Gogh, and some of his contemporaries frequently made use of the pigment chrome yellow that is known to show a tendency toward darkening. This pigment may correspond to various chemical compounds such as PbCrO4 and PbCr1-xSxO4, that may each be present in various crystallographic forms with different tendencies toward degradation. Investigations by X-ray diffraction (XRD), mid-Fourier Transform infrared (FTIR), and Raman instruments (benchtop and portable) and synchrotron radiation-based micro-XRD and X-ray absorption near edge structure spectroscopy performed on oil-paint models, prepared with in-house synthesized PbCrO4 and PbCr1-xSxO4, permitted us to characterize the spectroscopic features of the various forms. On the basis of these results, an extended study has been carried out on historic paint tubes and on embedded paint microsamples taken from yellow-orange/pale yellow areas of 12 Van Gogh paintings, demonstrating that Van Gogh effectively made use of different chrome yellow types. This conclusion was also confirmed by in situ mid-FTIR investigations on Van Goghs Portrait of Gauguin (Van Gogh Museum, Amsterdam).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000313668400031	Publication Date	2012-10-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700;1520-6882;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	79	Open Access
	Notes	Goa; Fwo			Approved	Most recent IF: 6.32; 2013 IF: 5.825
	Call Number	UA @ lucian @ c:irua:108707UA @ admin @ c:irua:108707			Serial	631
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	Author	Janssens, K.L.; Peeters, F.M.; Schweigert, V.A.
	Title	Magnetic field dependence of the exciton energy in a quantum disk			Type	A1 Journal article
	Year	2001	Publication	Physical review : B : condensed matter and materials physics	Abbreviated Journal	Phys Rev B
	Volume	63	Issue		Pages	205311
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Lancaster, Pa	Editor
	Language		Wos	000168937200058	Publication Date	2002-07-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0163-1829;1095-3795;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	81	Open Access
	Notes				Approved	Most recent IF: 3.836; 2001 IF: NA
	Call Number	UA @ lucian @ c:irua:37291			Serial	1869
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	Author	Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Dik, J.; Radepont, M.; Hendriks, E.; Geldof, M.; Cotte, M.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 2 : original paint layer samples			Type	A1 Journal article
	Year	2011	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	83	Issue	4	Pages	1224-1231
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The darkening of the original yellow areas painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is a phenomenon widely observed on several paintings by Vincent van Gogh, such as the famous different versions of Sunflowers. During our previous investigations on artificially aged model samples of lead chromate, we established for the first time that darkening of chrome yellow is caused by reduction of PbCrO4 to Cr2O3·2H2O (viridian green), likely accompanied by the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide]. In the second part of this work, in order to demonstrate that this reduction phenomenon effectively takes place in real paintings, we study original paint samples from two paintings of V. van Gogh. As with the model samples, in view of the thin superficial alteration layers that are present, high lateral resolution spectroscopic methods that make use of synchrotron radiation (SR), such as microscopic X-ray absorption near edge (μ-XANES) and X-ray fluorescence spectrometry (μ-XRF) were employed. Additionally, μ-Raman and mid-FTIR analyses were carried out to completely characterize the samples. On both paint microsamples, the local presence of reduced Cr was demonstrated by means of μ-XANES point measurements. The presence of Cr(III) was revealed in specific areas, in some cases correlated to the presence of Ba(sulfate) and/or to that of aluminum silicate compounds.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000287176900012	Publication Date	2011-02-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	84	Open Access
	Notes	; This research was funded by grants from ESRF (experiment EC-504) and by HASYLAB (experiments 11-20080130 EC and 11-20070157 EC) and was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Van Gogh Museum, Amsterdam, is acknowledged for their agreeable cooperation and for the authorization to publish the images of the paintings in this article. L.M. was financially supported by the Erasmus Placement in the framework of Lifelong Learning Programme (A.Y. 2009-2010). The EU Community's FP7 Research Infrastructures program under the CHARISMA Project (Grant Agreement 228330) is also acknowledged. ;			Approved	Most recent IF: 6.32; 2011 IF: 5.856
	Call Number	UA @ admin @ c:irua:88795			Serial	5571
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	Author	van der Snickt, G.; Dik, J.; Cotte, M.; Janssens, K.; Jaroszewicz, J.; de Nolf, W.; Groenewegen, J.; van der Loeff, L.
	Title	Characterization of a degraded cadmium yellow (CdS) pigment in an oil painting by means of synchrotron radiation based X-ray techniques			Type	A1 Journal article
	Year	2009	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	81	Issue	7	Pages	2600-2610
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	On several paintings of James Ensor (1860−1949), a gradual fading of originally bright yellow areas, painted with the pigment cadmium yellow (CdS), is observed. Additionally, in some areas exposed to light, the formation of small white-colored globules on top of the original paint surface is observed. In this paper the chemical transformation leading to the color change and to the formation of the globules is elucidated. Microscopic X-ray absorption near-edge spectroscopy (ì-XANES) experiments show that sulfur, originally present in sulfidic form (S2−), is oxidized during the transformation to the sulfate form (S6+). Upon formation (at or immediately below the surface), the highly soluble cadmium sulfate is assumed to be transported to the surface in solution and reprecipitates there, forming the whitish globules. The presence of cadmium sulfate (CdSO4·2H2O) and ammonium cadmium sulfate [(NH4)2Cd(SO4)2] at the surface is confirmed by microscopic X-ray diffraction measurements, where the latter salt is suspected to result from a secondary reaction of cadmium sulfate with ammonia. Measurements performed on cross sections reveal that the oxidation front has penetrated into the yellow paint down to ca. 1−2 ìm. The morphology and elemental distribution of the paint and degradation product were examined by means of scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS) and synchrotron radiation based micro-X-ray fluorescence spectrometry (SR ì-XRF). In addition, ultraviolet-induced visible fluorescence photography (UIVFP) revealed itself to be a straightforward technique for documenting the occurrence of this specific kind of degradation on a macroscale by painting conservators.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000264759400025	Publication Date	2009-03-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	91	Open Access
	Notes				Approved	Most recent IF: 6.32; 2009 IF: 5.214
	Call Number	UA @ admin @ c:irua:76415			Serial	5501
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	Author	Janssens, K.; Proost, K.; Falkenberg, G.
	Title	Confocal microscopic X-ray fluorescence at the HASYLAB microfocus beamline: characteristics and possibilities			Type	A1 Journal article
	Year	2004	Publication	Spectrochimica acta: part A: molecular and biomolecular spectroscopy	Abbreviated Journal	Spectrochim Acta A
	Volume	59	Issue		Pages	1637-1645
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000224848000020	Publication Date	2004-10-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1386-1425	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.536	Times cited	102	Open Access
	Notes				Approved	Most recent IF: 2.536; 2004 IF: 1.188
	Call Number	UA @ admin @ c:irua:49010			Serial	5555
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	Author	Alfeld, M.; Pedroso, J.V.; van Hommes, M.E.; van der Snickt, G.; Tauber, G.; Blaas, J.; Haschke, M.; Erler, K.; Dik, J.; Janssens, K.
	Title	A mobile instrument for in situ scanning macro-XRF investigation of historical paintings			Type	A1 Journal article
	Year	2013	Publication	Journal of analytical atomic spectrometry	Abbreviated Journal	J Anal Atom Spectrom
	Volume	28	Issue	5	Pages	760-767
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Scanning macro-X-ray fluorescence analysis (MA-XRF) is rapidly being established as a technique for the investigation of historical paintings. The elemental distribution images acquired by this method allow for the visualization of hidden paint layers and thus provide insight into the artist's creative process and the painting's conservation history. Due to the lack of a dedicated, commercially available instrument the application of the technique was limited to a few groups that constructed their own instruments. We present the first commercially available XRF scanner for paintings, consisting of an X-ray tube mounted with a Silicon-Drift (SD) detector on a motorized stage to be moved in front of a painting. The scanner is capable of imaging the distribution of the main constituents of surface and sub-surface paint layers in an area of 80 by 60 square centimeters with dwell times below 10 ms and a lateral resolution below 100 mu m. The scanner features for a broad range of elements between Ti (Z = 22) and Mo (Z = 42) a count rate of more than 1000 counts per second (cps)?mass percent and detection limits of 100 ppm for measurements of 1 s duration. Next to a presentation of spectrometric figures of merit, the value of the technique is illustrated through a case study of a painting by Rembrandt's student Govert Flinck (1615-1660).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000317674200019	Publication Date	2013-03-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0267-9477	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.379	Times cited	106	Open Access
	Notes	; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (IUAP VI/16). The text also presents the results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. M. Alfeld receives a Ph. D. fellowship of the Research Foundation-Flanders (FWO). We thank J. Langerock for allowing us to examine the portable altar triptych shown in Fig. 5. ;			Approved	Most recent IF: 3.379; 2013 IF: 3.396
	Call Number	UA @ admin @ c:irua:108517			Serial	5453
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	Author	Alfeld, M.; Janssens, K.; Dik, J.; de Nolf, W.; van der Snickt, G.
	Title	Optimization of mobile scanning macro-XRF systems for the in situ investigation of historical paintings			Type	A1 Journal article
	Year	2011	Publication	Journal of analytical atomic spectrometry	Abbreviated Journal	J Anal Atom Spectrom
	Volume	26	Issue	5	Pages	899-909
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Elemental distribution maps are of great interest in the study of historical paintings, as they allow to investigate the pigment use of the artist, to image changes made in the painting during or after its creation and in some cases to reveal discarded paintings that were later over painted. Yet a method that allows to record such maps of a broad range of elements in a fast, non-destructive and in situ manner is not yet commonly available; a dedicated mobile scanning XRF instrument might fill this gap. In this paper we present three self-built scanning macro-XRF instruments, each based on the experience gained with its precursor. These instruments are compared in terms of sensitivity and limits of detection, which includes a discussion of the use of polycapillary optics and pinhole collimators as beam defining devices. Furthermore, the imaging capabilities of the instruments are demonstrated in three exemplary cases: (parts of) historical paintings from the 15th to the 19th century are examined. These cases illustrate the value of element specific distribution maps in the study of historical paintings and allow in the case of Vincent van Gogh's Patch of Grass a direct comparison between in situ and synchrotron based scanning macro-XRF.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000289731900004	Publication Date	2011-03-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0267-9477	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.379	Times cited	107	Open Access
	Notes	; The investigation of the “Triptych of the Seven Sacraments'' was done in collaboration with Griet Steyaert, independent restorer, and Lizet Klaassen, Royal Museum of Fine Arts (Antwerp, Belgium). The investigation of ”Patch of Grass'' was realized in collaboration with Luuk van der Loeff, Kroller-Muller-Museum (Otterlo, The Netherlands). M. Alfeld is a PhD fellowship of the Research Foundation-Flanders (FWO). This research was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16) NACHO. The text also presents results of GOA "XANES meets ELNES'' (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0103.04, G.0689.06 and G.0704.08. Further, the work presented was sponsored by the Innovational Research Incentives Scheme of the Netherlands Organization for Scientific Research, NWO (proj. no. 016.118.303). ;			Approved	Most recent IF: 3.379; 2011 IF: 3.220
	Call Number	UA @ admin @ c:irua:89919			Serial	5758
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	Author	Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Verbeeck, J.; Tian, H.; Tan, H.; Dik, J.; Radepont, M.; Cotte, M.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 1 : artificially aged model samples			Type	A1 Journal article
	Year	2011	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	83	Issue	4	Pages	1214-1223
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	On several paintings by artists of the end of the 19th century and the beginning of the 20th Century a darkening of the original yellow areas, painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is observed. The most famous of these are the various Sunflowers paintings Vincent van Gogh made during his career. In the first part of this work, we attempt to elucidate the degradation process of chrome yellow by studying artificially aged model samples. In view of the very thin (1−3 μm) alteration layers that are formed, high lateral resolution spectroscopic methods such as microscopic X-ray absorption near edge (μ-XANES), X-ray fluorescence spectrometry (μ-XRF), and electron energy loss spectrometry (EELS) were employed. Some of these use synchrotron radiation (SR). Additionally, microscopic SR X-ray diffraction (SR μ-XRD), μ-Raman, and mid-FTIR spectroscopy were employed to completely characterize the samples. The formation of Cr(III) compounds at the surface of the chrome yellow paint layers is particularly observed in one aged model sample taken from a historic paint tube (ca. 1914). About two-thirds of the chromium that is present at the surface has reduced from the hexavalent to the trivalent state. The EELS and μ-XANES spectra are consistent with the presence of Cr2O3·2H2O (viridian). Moreover, as demonstrated by μ-XANES, the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide], is likely.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000287176900011	Publication Date	2011-02-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700;1520-6882;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	113	Open Access
	Notes	Iuap; Fwo			Approved	Most recent IF: 6.32; 2011 IF: 5.856
	Call Number	UA @ lucian @ c:irua:88794UA @ admin @ c:irua:88794			Serial	632
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	Author	Brenker, F.E.; Vollmer, C.; Vincze, L.; Vekemans, B.; Szymanski, A.; Janssens, K.; Szaloki, I.; Nasdala, L.; Joswig, W.; Kaminsky, F.
	Title	Carbonates from the lower part of transition zone or even the lower mantle			Type	A1 Journal article
	Year	2007	Publication	Earth and planetary science letters	Abbreviated Journal	Earth Planet Sc Lett
	Volume	260	Issue	1/2	Pages	1-9
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Effective CO2-storage in the shallow solid Earth mainly occurs by the formation of carbonates. Although the possibility of transport and storage of carbonates to great depth is demonstrated experimentally, ultra-deep mantle carbonates have not been found before. Applying several in situ analytical techniques on inclusions in diamonds from Juina (Brazil) originating from the lower part of the transition zone (> 580 km) or even the lower mantle (> 670 km), reveal the existence of deep Earth carbonates. These finding unquestionably show that at least locally carbonates exist within the deep Earth and may indicate that the Earth's global CO2-cycle has an ultra-deep extension.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000248883300001	Publication Date	2007-03-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0012-821x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.409	Times cited	156	Open Access
	Notes				Approved	Most recent IF: 4.409; 2007 IF: 3.873
	Call Number	UA @ admin @ c:irua:71387			Serial	5496
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	Author	Flynn, G.J.; Janssens, K.; Vekemans, B.; [et al.]
	Title	Elemental compositions of comet 81P/Wild 2 samples collected by Stardust			Type	A1 Journal article
	Year	2006	Publication	Science	Abbreviated Journal	Science
	Volume	314	Issue	5806	Pages	1731-1735
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000242833600046	Publication Date	2006-12-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0036-8075; 1095-9203	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	37.205	Times cited	174	Open Access
	Notes				Approved	Most recent IF: 37.205; 2006 IF: 30.028
	Call Number	UA @ admin @ c:irua:61923			Serial	5603
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	Author	Dik, J.; Janssens, K.; van der Snickt, G.; van der Loeff, L.; Rickers, K.; Cotte, M.
	Title	Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping			Type	A1 Journal article
	Year	2008	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	80	Issue	16	Pages	6436-6442
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Vincent van Gogh (1853−1890), one of the founding fathers of modern painting, is best known for his vivid colors, his vibrant painting style, and his short but highly productive career. His productivity is even higher than generally realized, as many of his known paintings cover a previous composition. This is thought to be the case in one-third of his early period paintings. Van Gogh would often reuse the canvas of an abandoned painting and paint a new or modified composition on top. These hidden paintings offer a unique and intimate insight into the genesis of his works. Yet, current museum-based imaging tools are unable to properly visualize many of these hidden images. We present the first-time use of synchrotron radiation based X-ray fluorescence mapping, applied to visualize a womans head hidden under the work Patch of Grass by Van Gogh. We recorded decimeter-scale, X-ray fluorescence intensity maps, reflecting the distribution of specific elements in the paint layers. In doing so we succeeded in visualizing the hidden face with unprecedented detail. In particular, the distribution of Hg and Sb in the red and light tones, respectively, enabled an approximate color reconstruction of the flesh tones. This reconstruction proved to be the missing link for the comparison of the hidden face with Van Goghs known paintings. Our approach literally opens up new vistas in the nondestructive study of hidden paint layers, which applies to the oeuvre of Van Gogh in particular and to old master paintings in general.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000258448100039	Publication Date	2008-07-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	178	Open Access
	Notes				Approved	Most recent IF: 6.32; 2008 IF: 5.712
	Call Number	UA @ admin @ c:irua:74466			Serial	5906
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