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Organisationseinheit der BAM
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- 8.5 Röntgenbildgebung (4)
Eingeladener Vortrag
- nein (31)
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.
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 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.
Gold mosaics, made from gold and glass, are one of the best expressions of Late Antique Byzantine and Early Islamic art. The gold alloys, whose composition seems to indicate that gold coins were re-used to fabricate the tesserae, can be used to provide information on the mosaics chronology. Monetary Byzantine gold is in fact characterized by the presence of Pt, which contents in the gold alloy change over time, but Pt must be measured in 0.2-0.4 µm thickness gold leaves that were beaten to be sandwiched between two glass layers.
To analyze this samples the D²XRF set-up at the BAMline at the BESSY synchrotron in Berlin was used. The combination of a crystal for wavelength dispersion and an energy resolving single photon counting pnCCD allows the realization of this very simple wavelength dispersive detection system. With this system an MDL of 1 μg/g for the determination of Pt in Au under optimal conditions can be reached.
Gold leaf tesserae from nine archaeological sites, covering the period that goes from the 5th c. to the 8th c., were analyzed. The presence of Pt in the majority of the samples confirmed the re-use of coins. The Pt contents separate the samples in three groups, one of which having the same chemical characteristics as the Byzantine gold could be compared to dated coins for chronology. The higher Pt contents for one of other groups suggest
Wilson´s disease, a rare genetic disorder of the copper metabolism, causes the copper accumulation in various organs, leading to manifold hepatic, neurological and psychiatric symptoms. To study the elemental distribution, human Wilson´s disease liver samples were analyzed by means of LA-ICP-MS. Results demonstrated an inhomogeneous copper and iron distribution in human liver with hotspots of very high intensities. Both elements were quantified by an external calibration using matrix-matched standards made of gelatin, showing concentrations up to several thousand micrograms per gram. Additionally, results were validated by means of synchrotron radiation based μXRF at the BAMline at BESSYII (Helmholtz-Zentrum Berlin).
Wilson´s disease (WD) is a rare genetic disorder of the copper metabolism, causing the accumulation of copper in different organs, including the liver, the central nervous system and cornea. This way, WD initiates manifold hepatic, neurological or psychiatric symptoms. To learn about the elemental distribution and present species in WD, liver samples were analyzed by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), micro X-ray fluorescence (μXRF) and X-ray absorption near edge structure spectroscopy (XANES).
Within this work, LA-ICP-MS was applied to study the distribution of copper and iron in human liver samples, which were collected by a liver biopsy of WD and control patients within a medical investigation. The analysis by LA-ICP-MS was performed with a 213 nm Nd:YAG laser using a spatial resolution of 10 μm and a scan rate of 20 μm/s. In a next step, copper and iron were quantified by LA-ICP-MS using homemade matrix-matched standards made of gelatin. Results showed an inhomogeneous copper and iron distribution in human liver with hotspots up to several thousand micrograms per gram liver within the hepatocytes.
Additionally, results for the elemental distribution in WD were validated by means of synchrotron radiation-based μXRF with a beam size of 4 μm at the BAMline at BESSYII (Helmholtz-Zentrum Berlin). Furthermore, XANES was performed to identify the present oxidation states of copper in WD, indicating a mixture of copper(I) and copper(II) within the liver tissue.
In the contemporary medicine, rhodanine staining is routinely used to determine the copper distribution in liver tissues. Nevertheless, this method does not provide results with a high sensitivity in comparison to LA-ICP-MS. Therefore, the presented LA-ICP-MS method offers a new possible diagnostic tool. These results may also contribute to a better understanding of Wilson´s disease and its development.
High Speed X-ray Imaging and Spectroscopy with pnCCDs: XRF, XRD and PIXE measurements (and others)
(2016)
For many years pnCCDs have been well known as X-ray detectors for spectroscopic imaging in
many fields of science: X-Ray Fluorescence analysis (XRF), X-ray Diffraction (XRD) with light
sources in large accelerator facilities as well as with laboratory light sources or with X-rays from
celestial sources in X-ray astronomy. A brief introduction in GEXRF (Grazing Emission XRF)
measurements with a laboratory laser produced plasma source will be given, PIXE (Particle Induced
X-ray Emission) measurements and D2XRF (Double Dispersive X-Ray Fluorescence) and Slicing
experiments with pnCCDs coupled to polycapillary optics performed at the BESSY synchrotron will
be shown. Energy-dispersive Laue diffraction with ultra-hard X-rays for the analysis of defects
in metals will conclude the overview of spectroscopic X-ray imaging measurements in the field of
structure and dynamics of matter.
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.
Airborne particulate matter is a topic of growing interest. Particles with aerodynamic diameters less than 10 μm (PM 10) and especially the fine fraction below 2.5 μm (PM2.5) are of particular importance, as they can enter the human respiratory system and cause acute and
chronic respiratory or cardiovascular diseases. The mass distribution of airborne particles in dependence of their diameters is well-known, but also the abundance and temporal variation of trace elements in air (mass concentrations down to the pg/m³ range) are crucial.
These elements originate from various natural (abrasion, erosion) and anthropogenic sources (combustion, road traffic), which complicate the discrimination between harmless and toxic emissions. Some new methods of investigation are therefore needed and X-ray fluorescence spectroscopy has ascertained ist huge potential in this matter, thanks to the possibility to determine simultaneously, in a time-resolved manner, the mass concentrations of critical elements which can be considered as markers of a potential toxic source. A method for the quantitative Analysis of airborne particles directly collected on sample substrates (30 mm quartz reflectors and 1" Si wafers suited for total-reflection X-ray fluorescence analysis (TXRF) will be presented.
Samplings were performed using a three- stage Dekati™ PM10 impactor (>10 μm, 2.5 to 10 μm and 1 to 2.5 μm) and a four-stage Sioutas Personal Cascade Impactor (>2.5 μm, 1 to 2.5 μm,0.5 to 1 μm and 0.25 to 0.5 μm) at indoor and outdoor sites at the Atominstitut (Vienna, Austria). Quantitative results of two outdoor test sampling campaigns (July 2016 and January 2017) will be presented and discussed. Low detection limits were assessed via TXRF and range from several 10 to several 100 pg/m³ depending on the element and particle size fraction.