136 research outputs found
MA-XRF for Historical Paintings: State of the Art and Perspective
No full textAccepted Author Manuscript(OLD) MSE-
Classification of soil aggregates using SEM-EDX hyperspectral data analysis
No full textSoil is a complex system characterized by peculiar chemical, physical and biological properties. Soil
characteristics are the results of the attributes of micrometric and submicrometric domains. For this reason,
the use of sensitive techniques with high spatial resolution is mandatory. Scanning electron microscopy
(SEM) is a very powerful analytical technique for the analysis of morphology and microstructure of the
soil and its components. When SEM is coupled with energy dispersive (EDX) or wavelength dispersive
(WDX) x-ray detectors, the chemical analysis of the sample can also be performed. The combination of
microstructural and chemical data can give information about elemental associations within minerals
or soil aggregates, allowing their detailed characterization. Chemical databases are not fully used and
scientists often superimpose different chemical maps in order to find correlations among element on the
base of different colour scales. However, by elaborating data this way, most of the objective hyperspectral
database information is lost and the obtained results rely on the scientist’s subjective choice. To overcome
this problem, in the present work “Datamuncher_gamma”, a software recently developed for the analysis of
SEM-EDX hyperspectral data , is presented and applied to study soil samples. Datamuncher_gamma allows
to obtain elemental maps from hyperspectral datasets and to compare the characteristic fluorescence lines
of all the elements found in the sample. The visual recognition of particular correlations then allows to
identify particular mineral phases and soil features.
Specifically, datamuncher_gamma was applied for the study of chromium polluted soil aggregates. SEMEDX
analysis were conducted on soil thin sections with a Zeiss Σigma 300 VP FEG-SEM working at 15 kV
and equipped with an Oxford EDX C-MaxN SDD.
Different element correlations with characteristic ratios were recognised. For example, Si vs Al scatterplots
were useful for the identification of different aluminosilicates and a more precise characterization was
obtained by comparing the Si signal with the signal of K, Ca and Mg. Chromium was found mostly
associated with aggregates having high C/O ratio. Among them, four different types of Cr-aggregates were
recognised on the base of Fe/Cr scatterplot.
Such hyperspectral approach using SEM-EDX data could be used to investigate many soil processes
regarding metal(loid) pollutants or micronutrients at the microscale
Das Bildungsprogramm des Deutschen Gewerkschaftsbundes, Kreis Alfeld (Leine) und "Arbeit und Leben"
No full textTiefenempfindlichkeit in der bildgebenden makro-RFA
No full textBildgebende makro-RFA findet in den letzten Jahren immer stärkere Verbreitung bei der zerstörungsfreien Untersuchung historischer Gemälde [1]. In dieser Technik wird die Oberfläche des Gemäldes schrittweise mit einem Röntgenstrahl von mehreren hundert Micrometern Durchmesser abgerastert. Dabei kann die Verteilung chemischer Elemente in Flächen von bis zu mehreren Quadratmetern untersucht werden. Durch die groβe Eindringtiefe der Röntgenstrahlen tragen nicht nur Elemente an der Oberfläche, sondern auch in tieferen Schichten, zu den aufgenommenen RFA Spektren bei, so dass auch Schichten untersucht werden können, die für das bloβe Auge nicht sichtbar sind. Diese Schichten können Aufschluss über Änderungen in der Kompositionen oder verworfene und übermalte Gemälde geben.Eine direkte Trennung der Signalen von der Oberfläche des Bildes und denen aus tieferen Lagen ist nicht direkt möglich, so dass es in machen Fällen fraglich ist, ob sich ein Element an der Oberfläche und in der endgültigen Komposition befindet.Um eine Tiefenempfindlichkleit zu erreichen haben wir einen RFA Scanner entwickelt der mittels mehrerer energiedispersiver Detektoren gleichzeitig Fluoreszensstrahlung mit vier verschiedenen Detektionswinkeln zwischen 25° und 45° registriert [2].Da die Absorption von Strahlung über die Weglänge im absorbierenden Medium und damit dem Detektionswinkel abhängt kann durch den Vergleich von Fluoreszensstrahlung die unter verschiedenen Detektionswinkeln aufgezeichnet wurde eine (begrenzte) Tiefenempfindlichkeit erreicht werden. Ähnliche Ergebnisse können durch den Vergleich der Intensitäten von Fluoreszenslinien unterschiedlicher Energie erreicht werden.Wir werden an ausgesuchten Fallstudien historischer Gemälde beide Ansätze miteinander und mit klassischen Tiefenprofilierungstechniken wie der konfokaler RFA [3] und Farbanschliffen vergleichen. [1] K. Janssens, M. Alfeld, G. Van der Snickt, W. De Nolf, F. Vanmeert, M. Radepont, L. Monico, J. Dik, M. Cotte, G. Falkenberg, C. Miliani, B.G. Brunetti, Annu. Rev. Anal. Chem. 6, 399 (2013).[2] M. Alfeld, K. Janssens, J. Dik, W. de Nolf, G. van der Snickt, J. Anal. At. Spectrom. 26, 899 (2011).[3] I. Reiche, K. Müller, M. Eveno, E. Itié, M. Menu, J. Anal. At. Spectrom. 26, 1715 (2012)
Debitum Gratulatorium, Quod Perillustri atq[ue] Generoso Domino Friederico ab Alfeld, Serenissimi Cimbrorum Ducis Regentis Consiliario Provinciali, Præfecto Trittaviensi & Reinbeccensi ... Debuit, Nunc verò Duplici Emblematum Triade, ex Gentilitiis Alfeldiorum insigniis ...Ex debito solvit, & solutum Ipso Friderici die, qui erat III Non. Martii ... obtulit ... Debitor M. Christianus von Stökken/ Pastor Ecclesiæ Trittaviensis
No full textDEBITUM GRATULATORIUM, QUOD PERILLUSTRI ATQ[UE] GENEROSO DOMINO FRIEDERICO AB ALFELD, SERENISSIMI CIMBRORUM DUCIS REGENTIS CONSILIARIO PROVINCIALI, PRÆFECTO TRITTAVIENSI & REINBECCENSI ... DEBUIT, NUNC VERÒ DUPLICI EMBLEMATUM TRIADE, EX GENTILITIIS ALFELDIORUM INSIGNIIS ...EX DEBITO SOLVIT, & SOLUTUM IPSO FRIDERICI DIE, QUI ERAT III NON. MARTII ... OBTULIT ... DEBITOR M. CHRISTIANUS VON STÖKKEN/ PASTOR ECCLESIÆ TRITTAVIENSIS
Debitum Gratulatorium, Quod Perillustri atq[ue] Generoso Domino Friederico ab Alfeld, Serenissimi Cimbrorum Ducis Regentis Consiliario Provinciali, Præfecto Trittaviensi & Reinbeccensi ... Debuit, Nunc verò Duplici Emblematum Triade, ex Gentilitiis Alfeldiorum insigniis ...Ex debito solvit, & solutum Ipso Friderici die, qui erat III Non. Martii ... obtulit ... Debitor M. Christianus von Stökken/ Pastor Ecclesiæ Trittaviensis ( - )
Title page ( - )
Πϱοϛφωνησιϛ Anacréontica. ( - )
Triados prioris Emblema Primum. ( - )
Triados prioris Emblema Secundum. ( - )
Triados Prioris Emblema Tertium. ( - )
Triados Posterioris Emblema Primum. ( - )
Triados Posterioris Emblema Secundum. ( - )
Triados posterioris Emblema Tertium. ( - )
In Insignia Ad Invidos. ( - )
Epigramma Votivum ad Diem Nominalem Friederici. ( - )
Anagramma triplex, ( - )
Epilogus Anacreonticus ad Imit. Cl. Taub: ( - )
Ad primum prioris Triados Emblema. ( - )
Section ( -
Investigation of the pigment use in the Tomba dei Rilievi and other tombs in the Etruscan Banditaccia Necropolis. PIGMENTGEBRAUCH IM GRAB DER RELIEFS UND ANDEREN GRÄBERN DER ETRUSKISCHEN BANDITACCIA NEKROPOLE
No full textThe use of pigments in antiquity, by Romans, Greeks and Egyptians, has been subject to a number of scientific studies. That of contemporary cultures, such as the Etruscans, have been described only in a small number of publications. We investigated the pigment use in five tombs of the Banditaccia Necropolis, near Cerveteri in central Italy: Tomba dei Rilievi (4th century BC), Tomba Mengarelli (7th century BC), Tumolo Policromo (4th century BC), Tomba delle Onde Marine (4th-3rd century BC) and an yet untitled recently excavated tomb (4th century BC (preliminary)). All were carved from the soft tuff bedrock.
A special focus was put on the Tomba dei Rilievi (Tomb of the Reliefs. It is for up to 45 bodies with 13 loculus (burial niches) the largest of the investigated tombs and the only one decorated with painted stucco reliefs
Depth discrimination in 2-dimensional XRF scans of historical paintings
No full textScanning macro-XRF is establishing rapidly as a technique for the investigation of historical paintings [1]. Here (up to) several square metres of the surface of the painting is scanned with an X-ray beam of typically several hundred micrometer diameter. The characteristic fluorescence radiation emitted by the elements present allows to identify the pigments used in the painting’s creation. Due to the penetrative nature of X-rays elements present in surface and sub-surface layers contribute to the acquired XRF spectra. This allows for the study of sub-surface layers resulting from overpainted sketches and discarded compositions, which cannot be studied by visible inspection.Although, a separation of signals emitted from surface and sub-surface layers is not directly possible in the XRF spectra acquired, the location of an element in the paint layer stratigraphy of a painting can be often deduced by comparison of the elemental distribution images with the visual impression of the painting. In this contribution, we will discuss the possibilities to distinct between surface and sub-surface layers based on absorption in covering paint layers. We have constructed a XRF scanner for historical paintings recording fluorescence radiation from four different detection angles between 25 and 45 degrees [2]. As the effective thickness of an absorber is dependent on the detection angle, the comparison of fluorescence radiation recorded from different angles allows to draw conclusions about the thickness of the covering layer and to determine whether a paint layer is present at the surface of a painting or below. A similar effect can be achieved by comparing the intensity of two fluorescence lines emitted by the same element with different energies, exploiting the energy dependence of X-ray absorption. Both approaches are somewhat limited as the self-absorption of X-rays in paint layers of variable composition and thickness cannot be separated from that in covering layers, so that care must be taken in the interpretation. The advantages and shortcomings of both approaches will be discussed on examples of selected historical paintings and the findings will be compared to depth profiling by confocal XRF and paint cross sections prepared from micro-samples taken from the painting.References[1] K. Janssens, M. Alfeld, G. Van der Snickt, W. De Nolf, F. Vanmeert, M. Radepont, L. Monico, J. Dik, M. Cotte, G. Falkenberg, C. Miliani, B.G. Brunetti, Annu. Rev. Anal. Chem. 6, 399 (2013).[2] M. Alfeld, K. Janssens, J. Dik, W. de Nolf, G. van der Snickt, J. Anal. At. Spectrom. 26, 899 (2011)
XAFS and species-specific imaging: new and old combinations for elucidating natural alteration reactions in pigmented materials
No full textCr K-edge full spectral XANES imaging of chrome yellow pigments: the Maia X-ray detector as a new possibility for studying the alteration process of these materials
No full textVan Gogh and alteration of chrome yellow pigments: new Cr-speciation studies using the Maia X-ray detector
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