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A set of ten calibration materials based on acrylonitrile-butadiene-styrene terpolymer (ABS) containing the elements Br, Pb, Cd, Cr, and Hg was produced in order to control polymer samples in regard to the restriction on the use of certain hazardous substances (RoHS) directive. The materials were produced with respect to the special demands of X-ray fluorescence analysis (XRF) and inductively coupled plasma mass spectrometry in combination with laser ablation (LA-ICP-MS).
The mass fractions of all elements were 0-1500 mg/kg and the materials were produced as granulates and solid discs with a diameter of 40 mm and thicknesses of 1, 2, and 6 mm. It could be shown that the signals measured by XRF strongly depend on the thickness of polymeric samples.
Macroscopic homogeneity was assessed with XRF measuring a total of 180 samples. The microscopic homogeneities were determined for a material with average elemental mass fractions with the aid of synchrotron radiation (SR) µ-XRF and LA-ICP-MS. Sufficient macroscopic and microscopic homogeneities for all elements could be achieved. It was observed that organic additives show a better homogeneity than oxides.
XRF and LA-ICP-MS were successfully calibrated with the new materials. Limits of detection were in the range of 0.4-22 mg/kg for XRF and 2.3-26.8 mg/kg for LA-ICP-MS. The materials are considered as candidate reference materials (RM) by the Federal Institute of Materials Research and Testing (BAM, Germany).
Within an interdisciplinary project, preliminary results of which were published in 2007, a group of 65 silver coins (denarii) of Trajan, evenly distributed over the entire span of his reign (2nd to 6th consulate), as well as 3 coins from the reign of his predecessor, the emperor Nerva (AD 9698), had been acquired on the coin market. These pieces could be cross-sectioned in order to carry out analyses. Measurements were performed with µ-XRF and µ-SRXRF to check the fineness of the denarius alloy as well as to investigate if the coins of the different consulates showed distinct traits concerning the main impurities which could suggest a change of ore sources. Furthermore, it was examined whether the influx of precious metals into the Roman treasury after Trajan's Dacian campaigns (AD 101/102 and 105/106) could have had any repercussions on the composition of the denarius alloy; comparative data was provided by the analysis of nine imitations of Roman Republican denarii presumably struck in Dacia. Documentation of the cross-sections was performed with SEM/EDX in order to clarify details concerning the specific microstructure of the coins. An enrichment of Ag of approx. 100 to 200 µm in the near surface regions of most of the coins could be observed, which is due to corrosion effects. Previous metallographic analyses done by several scholars had been inadequate to clarify the central numismatic and economic questions. With the presented analyses, it was possible to correct the results of the earlier research and to provide, for the first time, a secure basis of data for the investigation of the development of the silver alloy used for denarii in Trajan's reign.
In the determination of the provenance of gold in archaeological artifacts, trace elements are more significant than the main components. Several minute fragments of natural Carpathian gold-placer and primary-and some very small (a few milligrams) fragments of archaeological items were studied using micro Synchrotron Radiation X-Ray Fluorescence (micro SR-XRF) at the BESSY Synchrotron Facility in Berlin, Germany. The goal of the study was to identify the trace elements characterizing Carpathian gold, looking especially at Sn, Sb, Pb and Te, and to determine if the gold in the archaeological items is native or refined. Applications to the authentication and provenance of nine Dacian gold bracelets, koson coins and two Bronze Age items are presented.
Trace element concentrations in gold grains from various geological units in South Africa were measured in situ by field emission-electron probe microanalysis (FE-EPMA), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and synchrotron micro X-ray fluorescence spectroscopy (SR-µ-XRF). This study assesses the accuracy, precision and detection limits of these mostly non-destructive analytical methods using certified reference materials and discusses their application in natural sample measurement. FE-EPMA point analyses yielded reproducible and discernible concentrations for Au and trace concentrations of S, Cu, Ti, Hg, Fe and Ni, with detection limits well below the actual concentrations in the gold. LA-ICP-MS analyses required larger gold particles (> 60 µm) to avoid contamination during measurement. Elements that measured above detection limits included Ag, Cu, Ti, Fe, Pt, Pd, Mn, Cr, Ni, Sn, Hg, Pb, As and Te, which can be used for geochemical characterisation and gold fingerprinting. Although LA-ICP-MS measurements had lower detection limits, precision was lower than FE-EPMA and SR-µ-XRF. The higher variability in absolute values measured by LA-ICP-MS, possibly due to micro-inclusions, had to be critically assessed. Non-destructive point analyses of gold alloys by SR-µ-XRF revealed Ag, Fe, Cu, Ni, Pb, Ti, Sb, U, Cr, Co, As, Y and Zr in the various gold samples. Detection limits were mostly lower than those for elements measured by FE-EPMA, but higher than those for elements measured by LA-ICP-MS.
Shading Effects in SR-TXRF: Calcullations and Experimental Visualization using a Color X-ray Camera
(2014)
Shading Effects in SR-TXRF: Calculations and Experimental Visualization using a Color X-ray Camera
(2014)
Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (µXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D²XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products.
To better study the impact of nanoparticles on both in vitro and in vivo models, tissue distribution and cellular doses need to be described more closely. Here silver nanoparticles were visualized in alveolar macrophages by means of synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μXRF) with high spatial resolution of 3 × 3 μm2. For the spatial allocation of silver signals to cells and tissue structures, additional elemental labeling was carried out by staining with eosin, which binds to protein and can be detected as bromine signal with SR-μXRF. The method was compatible with immunostaining of macrophage antigens. We found that the silver distribution obtained with SR-μXRF was largely congruent with distribution maps from a subsequent laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of the same tissue sites. The study shows a predominant, though not exclusive uptake of silver into alveolar macrophages in the rat lung, which can be modeled by a similar uptake in cultured alveolar macrophages. Advantages and limitations of the different strategies for measuring nanoparticle uptake at the single cell level are discussed.
Synchrotron radiation sources with their unique properties in terms of intensity, polarization and adjustability offer a wide range of possibilities in materials research. A basic introduction about the creation and special properties of synchrotron radiation will be given. Examples of current work at BAMline, the high-energy measuring facility of the Federal Institute for Materials Research and Testing at the synchrotron BESSY, are used to illustrate the possibilities and limitations of existing measuring methods. It will be shown how the formation of corrosion layers can be tracked, how the abrasion of implants leads to the introduction of heavy metals into the surrounding bone matrix and how the detection of smallest impurities in gold is possible by optimizing the measuring conditions. Finally, an outlook at the hardware and software developments to be expected in the coming years is given.
The present study investigates early stages of ZIF-8 crystallization up to 5 minutes post mixing of precursor solutions. Dispersive X-ray Absorption Spectroscopy (DXAS) provides a refined understanding of the evolution of the coordination environment during ZIF-8 crystallization. Linear Combination Fiting (LCF) suggests tetrakis(1-methylimidazole)zinc2+ to be a suitable and stable mononuclear structure analogue for some early stage ZIF-8 intermediates. Our results pave the way for more detailed studies on physico-chemical aspects of ZIF-8 crystallization to better control tailoring ZIF-8 materials for specific applications.
The Color X-ray Camera CXC or SLcam® is an energy-resolving X-ray camera capable of energy- and space-resolved measurements. It consists of a high-speed CCD detector coupled to a polycapil-lary optic that conducts the X-ray photons from the probe to distinct pixels onto the detector. The camera is capable of fast acquisition of spatially and energy resolved fluorescence images. A dedicated software enables the acquisition and the online processing of the spectral data for all 69696 pixels, leading to a real-time visualization of the elements distribution in a sample. It was developed in a joint project with BAM, IFG Berlin and PN Sensors. In this contribution we will mainly discuss the use of the CXC at our beamline, the BAMline at BESSY II and imaging applications of the CXC from different areas, like biology and archaeometry. Additionally new developments for the use of the detector without optics, like wavelength dispersive detection or 1shot-XANES, will be presented.
In this study, we propose the use of nondestructive, depth-resolved, element-specific characterization using grazing exit X-ray absorption near-edge structure spectroscopy (GE-XANES) to investigate the corrosion process in compositionally complex alloys (CCAs). By combining grazing exit X-ray fluorescence spectroscopy (GE-XRF) geometry and a pnCCD detector, we provide a scanning-free, nondestructive, depth-resolved analysis in a sub-micrometer depth range, which is especially relevant for layered materials, such as corroded CCAs. Our setup allows for spatial and energy-resolved measurements and directly extracts the desired fluorescence line, free from scattering events and other overlapping lines. We demonstrate the potential of our approach on a compositionally complex CrCoNi alloy and a layered reference sample with known composition and specific layer thickness. Our findings indicate that this new GE-XANES approach has exciting opportunities for studying surface catalysis and corrosion processes in real-world materials.
A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved.
With the aim of improving limits of detection (LOD) of trace elements in a matrix with adjacent fluorescence energies, a simple double dispersive X-ray fluorescence detection system (D2XRF) was constructed to operate at the beamlines BAMline and the mySpot @ BESSY II. This system is based on the combination of a crystal analyzer with an energy resolving single photon counting pnCCD. Without further collimators, the efficient suppression of the background by the pnCCD and the good energy resolution of the crystal results in improved LOD. In first order reflections, an energy resolution of 13 eV for Cu Kα was reached, and an energy range of 1 keV was covered in one shot.
This new system was applied to the detection of platinum (Pt) in gold leaves with a LOD of 0.9 mg/kg, which is the lowest attained by totally non-destructive methods nowadays. The presence of Pt in gilded objects from Abydos and Byzantine mosaics provides vital information, as it indicates the alluvial origin of the gold for these examples.
Partial least squares (PLS) regression-based methods have been proven to be a good alternative for quantification in X-ray fluorescence spectroscopy. These methods are fast and easy to use though giving satisfactory results under certain conditions. One of these conditions is the necessity of having a great number of spectra to build the model (training set). The choice of the constituent concentration range in the training set has a big influence on the accuracy of the model. Better accuracy is obtained if the model is built in relatively narrow regions containing (or close to) the real concentration value.
In the present work, Monte Carlo (MC) simulated spectra are used to form the training set. The advantage to use MC generated training spectra is the unlimited availability of perfect standards.
This paper aims to improve the accuracy of the method by introducing a multiple step procedure in order to build the PLS model using narrow concentration range close to (or containing) the real concentration values in the samples to be measured.
This approach consists of an initial guess of the constituents' concentrations and a preliminary PLS model before building the final model. The prediction of ten MC simulated alloy standard samples containing Ti, Mn, Fe, Co, Cu, Zn, Sr, Zr, and Mo using this method allowed to have average relative prediction errors less than 5% for elements with narrow concentration ranges.
Evaluation of total reflection X-ray fluorescence (TXRF) analysis using a color X-ray camera (CXC)
(2013)
Adaptive Kanalreduktion eines hyperspektralen Bilddatensatzes kombiniert mit k-mean Clustering
(2014)
Slicing - A New Method For Non Destructive 3D Elemental Sensitive Characterization Of Materials
(2013)
Slicing - A New Method For Non Destructive 3D Elemental Sensitive Characterization Of Materials
(2014)
News from the BAMline
(2017)
Gold ist eines der sieben schon im Altertum bekannten Metalle und wurde wg. seines Glanzes und seiner Seltenheit von alters her als Tauschmittel und zur Herstellung von Schmuck benutzt. Außerdem ist es einfach bearbeitbar und weitestgehend gegen chemische Einflüsse resistent. Die Untersuchungen von Gold mit synchrotronstrahlungsangeregter Röntgenfluoreszenzanalyse sind zerstörungsfrei und geben Auskunft über die in der untersuchten Probe vorhandenen chemischen Elemente. Bei den hier vorgestellten Untersuchungen an der BAMline stehen Fragestellungen wie Herkunft, Herstellungsverfahren und Zusammengehörigkeit von Goldfunden im Vordergrund. Die verschiedenen Fragestellungen werden an einer Reihe von Beispielen erläutert die vom Wikingerschatz aus Hiddensee über die Himmelsscheibe von Nebra bis hin zu Funden aus Ägypten langen. Zusätzlich werden die modernen Messmethoden vorgestellt, die am Synchrotron heutzutage zur Verfügung stehen.
Die Eigenschaften und die Verlässlichkeit von Materialien jeglicher Art sind seit jeher die Grundlagen der Technik einer Gesellschaft. Tiefgreifende Kenntnisse über sie sind deshalb eine Voraussetzung um neue Produkte zu entwickeln, Verlässlichkeit zu gewährleisten, oder aber auch, wie in der Archäometrie, Kenntnisse über die Vergangenheit zu gewinnen. Ein Schlüssel zum Verständnis ist das Wissen über die chemische Zusammensetzung und die Struktur von Materialien Die Analyse mit Synchrotronstrahlung bietet hierfür herausragende Werkzeuge an, die zerstörungsfrei und hochsensitiv sind. Mit Röntgenfluoreszenzanalyse kann die elementare Zusammensetzung in winzigen Proben bis auf μg/g bestimmt werden. Anwendungsbeispiele aus verschiedenen Themengebieten, aber besonders von archäologischen Fragestellungen wie z.B. dem Goldfund von Bernstorf werden im Vortrag vorgestellt.
Gold ist eines der sieben schon im Altertum bekannten Metalle und wurde wg. seines Glanzes und seiner Seltenheit von alters her als Tauschmittel und zur Herstellung von Schmuck benutzt. Außerdem ist es einfach bearbeitbar und weitestgehend gegen chemische Einflüsse resistent.
Die Untersuchungen von Gold mit synchrotronstrahlungsangeregter Röntgenfluoreszenzanalyse sind zerstörungsfrei und geben Auskunft über die in der untersuchten Probe vorhandenen chemischen Elemente.
Bei den hier vorgestellten Untersuchungen an der BAMline stehen Fragestellungen wie Herkunft, Herstellungsverfahren und Zusammengehörigkeit von Goldfunden im Vordergrund. Die verschiedenen Fragestellungen werden an einer Reihe von Beispielen erläutert die vom Wikingerschatz aus Hiddensee über die Himmelsscheibe von Nebra bis hin zu Funden aus Ägypten langen. Zusätzlich werden die modernen Messmethoden vorgestellt, die am Synchrotron heutzutage zur Verfügung stehen.
The gold finds from Bernstorf, in the Freising district of Bavaria, were discovered in 1998, in the area of a Bronze Age settlement. First analyses with X-ray fluorescence (XRF) revealed gold of an unusually high purity grade, which was explained by the use of cementation techniques. A newer analysis with laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) indicated an even higher purity. The analytical results were the starting point of an ongoing discussion. In this study, we re-analysed 11 gold samples with Synchrotron radiation–induced X-ray fluorescence at the BAMline at BESSY. In a thorough analysis, different excitation and detection conditions were applied to confirm or disprove the previous results. It was shown that the purity of the gold from the specimen is higher than 99.9%. The main impurities are silver in a range between 20 and 200 μg/g and copper between 1 and 10 μg/g. The results are in very good agreement with the LA–ICP–MS measurements and provide basic information for discussions about provenance, processing techniques or considerations of authenticity.
The Color X-ray Camera CXC or SLcam® is an energy-resolving X-ray camera capable of energy- and space-resolved measurements. It consists of a high-speed CCD detector coupled to a polycapil-lary optic that conducts the X-ray photons from the probe to distinct pixels onto the detector.
The camera is capable of fast acquisition of spatially and energy resolved fluorescence images. A dedicated software enables the acquisition and the online processing of the spectral data for all 69696 pixels, leading to a real-time visualization of the elements distribution in a sample. It was developed in a joint project with BAM, IFG Berlin and PN Sensors.
In this contribution we will mainly discuss the use of the CXC at our beamline, the BAMline at BESSY II and imaging applications of the CXC from different areas, like biology and archaeometry. Additionally new developments for the use of the detector without optics, like wavelength dispersive detection or 1shot-XANES, will be presented.
EXAFS analysis of pure elements, binary and ternary equiatomic refractory alloys within the Nb-Zr-Ti-Hf- Ta system is performed at the Nb and Zr K-edges to analyze the evolution of the chemical local environ- ment and the lattice distortion. A good mixing of the elements is found at the atomic scale. For some compounds, a distribution of distances between the central atom and its neighbors suggests a distortion of the structure. Finally, analysis of the Debye-Waller parameters shows some correlation with the lat- tice distortion parameter δ², and allows to quantify experimentally the static disorder in medium entropy alloys.
A major source of capacity fade of the common vanadium redox flow battery (VRFB) is the vanadium ion transport through the separator. However, different transport models disagree significantly in the diffusion coefficient for the different V species and the influence of different transport mechanisms. The underlying hypothesis of this work is that reactions inside the membrane are partly responsible for these discrepancies. Accordingly, it was investigated if redox reactions inside the nanoscopic water body of Nafion 117 can occur. X-ray absorption near edge structure spectroscopy (XANES) was used to distinguish between the different V species inside hydrated Nafion 117 and novel PVDF-based membranes. It was validated that the speciation of vanadium can be performed using the pre-edge peak energy and intensity. The experiments were performed as follows: strips of the membrane were exposed from one site to a V3+ solution (green) and from the other site to a VO2+ solution (yellow). The ions could diffuse into the membrane from both sides. A change of color of the membrane strip was observed. The blue color in the middle of the strip indicated that VO2+ was formed where V3+ and VO2+ got in contact. Using XANES this reaction inside Nafion was proven.
Sixteen Ayyubid-Mamluk glazed pottery sherds were analyzed in order to identify and characterize the elemental composition to determine their provenance. The tested sherds were collected from the historical site of Karak Castle, southern Jordan.
Chemical analysis for the sixteen samples has been carried out using Synchrotron Radiation X-ray Fluorescence Spectrometry (SR-XRF) Technique. Furthermore, the semiquantitative analysis of the elements Fe – Cu – Zn – Br – Rb – Sr – Y – Zr – Nb – Mo – Pd – Ag – Cd and Pb has been performed for the samples based on Principal Component Analysis (PCA) and hierarchical Cluster Analysis with Bray-Curtis in order to define grouping of different glazed pottery by obtaining information on their similarity and clustering. The results of chemical analysis provided persuasive evidence that the Karak Castle pottery sherds have at least three different sources of provenance.
In this talk an overview about artificial intelligence/machine learning applications @BAMline is given. In the first part, the use of neural networks for the quantification of XRF measurements and the decoding of coded-aperture measurements are shown. Then it is shown how Gaussian processes and Bayesian statistics can be used to achieve an optimal alignment of the set-up and in general for optimization of measurements.