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“An extensive multisensor hyperspectral benchmark datasets of intimate mixtures of mineral powders”. Koirala B, Rasti B, Bnoulkacem Z, De Lima Ribeiro A, Madriz Y, Herrmann E, Gestels A, De Kerf T, Janssens K, Steenackers G, Gloaguen R, Scheunders P, , 5890 (2023). http://doi.org/10.1109/IGARSS52108.2023.10281467
Abstract: Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain.In this work, we generated a comprehensive hyperspectral dataset of intimate mineral powder mixtures by homogeneously mixing five different clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide). In total 325 samples were prepared. Among the 325 samples, 60 mixtures were binary, 150 were ternary, 100 were quaternary, and 15 were quinary. For each mixture (and pure clay powder), reflectance spectra are acquired by 13 different sensors, with a broad wavelength range between the visible and the long-wavelength infrared regions (i.e., between 350 nm and 15385 nm) and with a large variation in sensor types, platforms, and acquisition conditions. We will make this dataset public, to be used by the community for the validation of nonlinear unmixing methodologies (https://github.com/VisionlabUA/Multisensor_datasets)
Keywords: P1 Proceeding; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)
DOI: 10.1109/IGARSS52108.2023.10281467
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“Chemical mapping of the degradation of geranium lake in paint cross sections by MALDI-MSI”. Alvarez-Martin A, Quanico J, Scovacricchi T, Avranovich Clerici E, Baggerman G, Janssens K, Analytical chemistry 95, 18215 (2023). http://doi.org/10.1021/ACS.ANALCHEM.3C03992
Abstract: Matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has become a powerful method to extract spatially resolved chemical information in complex materials. This study provides the first use of MALDI-MSI to define spatial–temporal changes in oil paints. Due to the highly heterogeneous nature of oil paints, the sample preparation had to be optimized to prevent molecules from delocalizing. Here, we present a new protocol for the layer-specific analysis of oil paint cross sections achieving a lateral resolution of 10 μm and without losing ionization efficiency due to topographic effects. The efficacy of this method was investigated in oil paint samples containing a mixture of two historic organic pigments, geranium lake and lead white, a mixture often employed in the work of painter Vincent Van Gogh. This methodology not only allows for spatial visualization of the molecules responsible for the pink hue of the paint but also helps to elucidate the chemical changes behind the discoloration of paintings with this composition. The results demonstrate that this approach provides valuable molecular compositional information about the degradation pathways of pigments in specific paint layers and their interaction with the binding medium and other paint components and with light over time. Since a spatial correlation between molecular species and the visual pattern of the discoloration pattern can be made, we expect that mass spectrometry imaging will become highly relevant in future degradation studies of many more historical pigments and paints.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS); Ecosphere
DOI: 10.1021/ACS.ANALCHEM.3C03992
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“A combined experimental and computational approach to understanding CdS pigment oxidation in a renowned early 20th century painting”. Mayda S, Monico L, Krishnan D, De Meyer S, Cotte M, Garrevoet J, Falkenberg G, Sandu ICA, Partoens B, Lamoen D, Romani A, Miliani C, Verbeeck J, Janssens K, Chemistry of materials 35, 10403 (2023). http://doi.org/10.1021/ACS.CHEMMATER.3C01470
Abstract: Cadmium sulfide (CdS)-based yellow pigments have been used in a number of early 20th century artworks, including The Scream series painted by Edvard Munch. Some of these unique paintings are threatened by the discoloration of these CdS-based yellow oil paints because of the oxidation of the original sulfides to sulfates. The experimental data obtained here prove that moisture and cadmium chloride compounds play a key role in promoting such oxidation. To clarify how these two factors effectively prompt the process, we studied the band alignment between CdS, CdCl2, and Cd-(OH)Cl as well as the radicals center dot OH and H3O center dot by density functional theory (DFT) methods. Our results show that a stack of several layers of Cd-(OH)Cl creates a pocket of positive holes at the Cl-terminated surface and a pocket of electrons at the OH-terminated surface by leading in a difference in ionization energy at both surfaces. The resulting band alignment indicates that Cd-(OH)Cl can indeed play the role of an oxidative catalyst for CdS in a moist environment, thus providing an explanation for the experimental evidence.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Antwerp X-ray Imaging and Spectroscopy (AXIS)
DOI: 10.1021/ACS.CHEMMATER.3C01470
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“Reconstructing Sweerts : practical insights into the historical dark halo technique based on paint reconstructions”. Derks K, Youchaeva M, Van der Snickt G, Van der Stighelen K, Janssens K, , 259 (2024)
Keywords: P1 Proceeding; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
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“A multisensor hyperspectral benchmark dataset for unmixing of intimate mixtures”. Koirala B, Rasti B, Bnoulkacem Z, de Lima Ribeiro A, Madriz Y, Herrmann E, Gestels A, De Kerf T, Lorenz S, Fuchs M, Janssens K, Steenackers G, Gloaguen R, Scheunders P, IEEE sensors journal 24, 4694 (2024). http://doi.org/10.1109/JSEN.2023.3343552
Abstract: Optical hyperspectral cameras capture the spectral reflectance of materials. Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain. In this work, we generated a comprehensive laboratory ground truth dataset of intimately mixed mineral powders. For this, five clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide) were mixed homogeneously to prepare 325 samples of 60 binary, 150 ternary, 100 quaternary, and 15 quinary mixtures. Thirteen different hyperspectral sensors have been used to acquire the reflectance spectra of these mixtures in the visible, near, short, mid, and long-wavelength infrared regions (350-15385) nm. Overlaps in wavelength regions due to the operational ranges of each sensor and variations in acquisition conditions resulted in a large amount of spectral variability. Ground truth composition is given by construction, but to verify that the generated samples are sufficiently homogeneous, XRD and XRF elemental analysis is performed. We believe these data will be beneficial for validating advanced methods for nonlinear unmixing and material composition estimation, including studying spectral variability and training supervised unmixing approaches. The datasets can be downloaded from the following link: https://github.com/VisionlabHyperspectral/Multisensor_datasets.
Keywords: A1 Journal article; Engineering sciences. Technology; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)
DOI: 10.1109/JSEN.2023.3343552
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“Correlated x-ray fluorescence and ptychographic nano-tomography on Rembrandt's The Night Watch reveals unknown lead “layer””. Broers FTH, Verslype I, Bossers KW, Vanmeert F, Gonzalez V, Garrevoet J, van Loon A, va Duijn E, Krekeler A, De Keyser N, Steeman I, Noble P, Janssens K, Meirer F, Keune K, Science Advances 9, eadj9394 (2023). http://doi.org/10.1126/SCIADV.ADJ9394
Abstract: The Night Watch, one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a-so far unknown-lead-containing “layer”, which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied. This layer might explain the presence of lead soap protrusions in areas where no other lead components are present. In addition to the three-dimensional elemental mapping, ptychography visualizes and quantifies components not detectable by hard x-ray fluorescence such as the organic fraction and quartz. The first-time use of this combination of synchrotron-based techniques on a historic paint micro-sample shows it to be an important tool to better interpret the results of noninvasive imaging techniques operating on the macroscale.
Keywords: A1 Journal article; Engineering sciences. Technology; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
DOI: 10.1126/SCIADV.ADJ9394
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“The use of scanning X-ray microprobe for simultaneous XRF/XRD studies of fly-ash particles”. Rindby A, Engström P, Janssens K, Journal of synchotron radiation 4, 228 (1997)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Micro-distribution of heavy elements in highly inhomogeneous particles generated from μ-beam XRF/XRD analysis”. Rindby A, Engström P, Janssens K, Osán J, Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms 124, 591 (1997)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.109
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“Provenance analysis of Roman glass from the 1st-6th century A.D”. Aerts A, Janssens K, Vincze L, Vekemans B, Adams F, Haller M, Radtke M, Knöchel A, HASYLAB Jahresbericht , 918 (1996)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Quantification of SY-XRF measurements at the X-ray microprobe”. Haller M, Radtke M, Knöchel A, Clöck W, Sutton S, Janssens K, Vincze L, HASYLAB Jahresbericht , 956 (1996)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Composition of 15-17th century archaeological glass vessels excavated in Antwerp, Belgium”. Janssens KH, Deraedt I, Schalm O, Veeckman J, Mikrochimica acta: supplementum 15, 253 (1998)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Fluorescent tomography of metals in fly-ash particles at beamline L”. Vincze L, Vekemans B, Janssens K, Adams F, Haller M, HASYLAB Jahresbericht 1997 1, 959 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Evaluation of a Monte Carlo simulation for EDXRF spectrometers at beamline BW5, HASYLAB”. Vincze L, Vekemans B, Janssens K, Adams F, Lippmann T, HASYLAB Jahresbericht 1997 1, 1043 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Composition of 15-17th century archaeological glass vessels excavated in Antwerp, Belgium”. Janssens K, de Raedt I, Vincze L, Vekemans B, Adams F, Haller M, Knöchel A, HASYLAB Jahresbericht 1997 1, 937 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Interpretation of cappilary generated spatial and angular distribution of X-rays: theoretical modeling and experimental verification using the European Synchrotron Radiation Facility Optical Beamline”. Vincze L, Janssens K, Adams F, Engström P, Rindby A, The review of scientific instruments 69, 3494 (1998). http://doi.org/10.1063/1.1149127
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.515
DOI: 10.1063/1.1149127
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“Special issue: Proceedings of the 15th International Congress on X-ray Optics and Microanalysis”. Janssens K, Journal of analytical atomic spectroscopy 14, 357 (1999)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Compositional distinctions between 16th century “Façon-de-Venise&rdquo, and Venetian glass vessels, excavated in Antwerp, Belgium”. Deraedt I, Janssens K, Veeckman J, Journal of analytical atomic spectroscopy 14, 483 (1999). http://doi.org/10.1039/A808385A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A808385A
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“Analyses of petrified wood by electron, X-ray and optical microprobes”. Kuczumov A, Vekemans B, Schalm O, Dorriné, W, Chevallier P, Dillmann P, Ro C-U, Janssens K, Van Grieken R, Journal of analytical atomic spectroscopy 14, 435 (1999). http://doi.org/10.1039/A806748A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A806748A
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“Monte-Carlo simulation of the coherent backscattering of electrons in a ballistic system”. Janssens KL, Peeters FM, Superlattices and microstructures 25, 615 (1999). http://doi.org/10.1006/spmi.1999.0697
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.123
DOI: 10.1006/spmi.1999.0697
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“Evaluation of polycapillary lenses as focussing elements in sub-mm XRF analysis of artistic objects”. Vekemans B, Janssens K, Adams F, Andong L, He Y, Yiming Y page 278 (1998).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Micro-analysis of artists' pigments by grazing-emission X-ray fluorescence spectrometry”. Claes M, van Ham R, Janssens K, Van Grieken R, Klockenkämper R, von Bohlen A, Advances in X-ray analysis 41, 262 (1999)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Optimization of tapered capillary optics for use at the microfocus beamline (ID 13) at the European Synchroton Radiation Facility”. Vincze L, Janssens K, Adams F, Rindby A, Engström P, Advances in X-ray analysis 41, 252 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Samenstelling van 15de- tot 17de-eeuwse glazen voorwerpen opgegraven in Antwerpen: deel 1”. de Raedt I, Janssens K, Veeckman J, Adams F, Journaal van de Belgische Vereniging voor Glastechnieken , 9 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Samenstelling van 15de- tot 17de-eeuwse glazen voorwerpen opgegraven in Antwerpen: deel 2”. de Raedt I, Janssens K, Veeckman J, Adams F, Journaal van de Belgische Vereniging voor Glastechnieken , 5 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Trace-level microanalysis of Roman glass from Khirbet Qumran, Israel”. Aerts A, Janssens K, Adams F, Journal of archaeological science 26, 883 (1999). http://doi.org/10.1006/JASC.1999.0397
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.602
DOI: 10.1006/JASC.1999.0397
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“Echt of namaak? Venetiaans glas uit het oude Antwerpen”. de Raedt I, Janssens K, Veeckman J, De wetenschappelijke bibliotheek 67, 58 (1999)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Localised and non-destructive analysis of metallic artefacts from ancient Egypt by means of a compact μ-XRF instrument”. Vittiglio G, Janssens K, Adams F, Oost A, Spectrochimica acta: part B : atomic spectroscopy 54, 1697 (1999). http://doi.org/10.1016/S0584-8547(99)00100-7
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.241
DOI: 10.1016/S0584-8547(99)00100-7
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“X-ray fluorescence microtomography: experiment and reconstruction”. Simionovici AS, Chukalina M, Drakopoulos M, Snigireva I, Snigirev A, Schroer C, Lengeler B, Janssens K, Adams F page 304 (1999).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Monte Carlo simulation of X-ray fluorescence and scattering tomography experiments”. Vincze L, Janssens K, Vekemans B, Adams F page 328 (1999).
Keywords: H1 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1117/12.363736
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“Monte Carlo simulation of X-ray fluorescence spectra: part 4: photon scattering at high X-ray energies”. Vincze L, Janssens K, Vekemans B, Adams F, Spectrochimica acta: part B : atomic spectroscopy , 1711 (1999). http://doi.org/10.1016/S0584-8547(99)00094-4
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.241
DOI: 10.1016/S0584-8547(99)00094-4
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