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Sauropod dinosaurs were typically one magnitude larger than any other living or extinct terrestrial animal. This sheer size of the sauropod leads to scale effects in their biology and physiology that still are inadequately understood. The... more
Sauropod dinosaurs were typically one magnitude larger than any other living or extinct terrestrial animal. This sheer size of the sauropod leads to scale effects in their biology and physiology that still are inadequately understood. The only remnants of the sauropods are their fossilized bones. These fossilized bones have sustained burial for some hundred million years and thus may have experienced significant diagenetic changes. These diagenetic changes often do not affect bone preservation on the histological level, but may lead to significant alterations of the bone microstructure. Here the influence of diagenesis on the microstructure of fossilized sauropod bones using femur cross section of Brachiosaurus brancai that was excavated in the Tendaguru beds in Tanzania is investigated. The element distribution in this dinosaur bone is studied by a combination of micro-X-ray-fluorescence (μ-XRF) using synchrotron radiation and energy dispersive X-ray analyses (EDX) in the scanning ...
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Experimental measurement of the spectral distribution emitted by an X-ray tube is presented using a solid state detector. Spectral distributions of several X-ray tubes differing in the material of the anode and its geometry have been... more
Experimental measurement of the spectral distribution emitted by an X-ray tube is presented using a solid state detector. Spectral distributions of several X-ray tubes differing in the material of the anode and its geometry have been measured and compared. Numerical values and relevant data for Cr, Cu, Mo, Rh and W X-ray tubes are presented.
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1) Atominstitut, Technische Universitaet Wien, Stationallee 2, 1020 Vienna, Austria 2) Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept., Hanusch Hospital, Vienna,... more
1) Atominstitut, Technische Universitaet Wien, Stationallee 2, 1020 Vienna, Austria 2) Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept., Hanusch Hospital, Vienna, Austria 3) Department of Orthopaedic Surgery, Vienna General Hospital, Medical Univ. of Vienna, Austria 4) Karlsruhe Institute of Technology, Institute for Synchrotron Radiation, Hermann-vonHelmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
To use the power of Total Reflection X-ray Fluorescence Analysis (TXRF) as an analytical method for very low detection limits on surfaces it is necessary to have a monoenergetic, energy adjustable x-ray beam with an intensity as high as... more
To use the power of Total Reflection X-ray Fluorescence Analysis (TXRF) as an analytical method for very low detection limits on surfaces it is necessary to have a monoenergetic, energy adjustable x-ray beam with an intensity as high as possible. Therefore a wide band pass monochromator is desired because it increases the flux of photons impinging on the sample and an energywidth of up to 200 eV does not affect the choice of exciting or suppressing a particular element. The importance of the high flux of photons within the energyband chosen will result in improved sensitivity and finally in better detection limits. Multilayers (ML) produced at PSI have been tested and succesfully used for that purpose. Alignment of the TXRF set-up for a given energy is time consuming and therefore a stable beam geometry is required for the energies adjusted. So in case of only one ML in the beam path this can not be fulfilled and requires a realignment of the TXRF set-up for each energy. A double ML...
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Abstract The confocal μ XRF spectrometer of Atominstitut (ATI) was transported and set up at the X-ray Fluorescence beamline at Elettra - Sincrotrone Trieste. It was successfully adjusted to the incoming beam (9.2 keV). Test measurements... more
Abstract The confocal μ XRF spectrometer of Atominstitut (ATI) was transported and set up at the X-ray Fluorescence beamline at Elettra - Sincrotrone Trieste. It was successfully adjusted to the incoming beam (9.2 keV). Test measurements on a free-standing Cu wire were performed to determine the size of the focused micro-beam (non-confocal mode, 56 × 35 μ m 2 ) and the size of the confocal volume (confocal mode, 41 × 24 × 34 μ m 2 ) for the Cu–K α emission. In order to test the setup’s capabilities, two areas on different human bone samples were measured in confocal scanning mode. For one of the samples the comparison with a previous μ XRF measurement, obtained with a low power X-ray tube in the lab, is presented.
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ABSTRACT Handheld or mobile XRF spectrometers are employed as a routine analytical tool in the most of the museum conservation laboratories for performing non-invasive analyses. In particular, the micro-XRF analysis of metal artefacts... more
ABSTRACT Handheld or mobile XRF spectrometers are employed as a routine analytical tool in the most of the museum conservation laboratories for performing non-invasive analyses. In particular, the micro-XRF analysis of metal artefacts utilizing exciting x-ray beams with spot sizes at the range of about 50-100 micrometers presents features that comply with certain requirements, namely minimum intervention (if necessary) on the surface and the possibility to characterize small decoration features or very localized regions, such as solderings, elucidating thus the manufacturing process. Moreover, the contribution to the diagnosis of surface alteration products offers invaluable help to the implementation of conservation practices. However, the rapid evolution of micro-XRF spectrometry applications was not followed with adequate standardization of the technique in terms of the calibration, the operating-measurement procedures and in general of best practices. In mobile micro-and milli-probe XRF analysis of metal alloys the precision and accuracy in the quantitative analysis or the influence of the heterogeneity and polycrystalline texture of metal alloys, are issues still open for discussion and consideration 1,2 . Applications from in-situ XRF campaigns conducted by INP-Demokritos at various Mediterranean museums' metal collections 2 (Palace Armoury Museum in Malta, Damascus Archaeological Museum in Syria, Yarmouk University in Jordan and the Ancient Messene museum in Greece), but also by the IAEA Seibersdorf laboratories in cooperation with the Kunsthistorisches Museum (KHM) and Vienna University of Technology will be presented 3 . Questions related to the raw metal composition, manufacturing process (gilding, surface decoration and finishing), type and distribution of corrosion products were addressed in these studies. Laboratory calibration measurements provided optimization of the measuring conditions, whereas a Fundamental Parameter (FP) based approach was developed for the quantification accounting properly for the x-ray lens transmission efficiency. Finally, simple empirical quantification schemes have been also studied and evaluated for certain type of alloys (like the Cu-Sn binary alloys), in order to assess to which extent a standardized procedure is applicable in quantitative XRF analysis.
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Total reflection X‐ray fluorescence analysis (TXRF) is a special method of energy‐dispersive X‐ray fluorescence analysis extending EDXRF to the ultra trace element level. The achievable detection limits depend on the excitation source and... more
Total reflection X‐ray fluorescence analysis (TXRF) is a special method of energy‐dispersive X‐ray fluorescence analysis extending EDXRF to the ultra trace element level. The achievable detection limits depend on the excitation source and are in the range of picograms to femtograms. Only small amounts of sample are required and the quantification by adding one element as an internal standard is
Research Interests: Materials Science, Environmental Monitoring, Synchrotron Radiation, Synchrotron, Thin Film, and 10 moreAbsorption spectroscopy, Optical physics, X-Ray Optics, Total Internal Reflection, Trace element, Total Reflection X-ray Fluorescence, Surface Analysis, X ray Fluorescence, Wafer, and Trace element analysis
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Atominstitut der Österreichischen Universitäten, TU Wien, Stadionallee 2, A 1020 Vienna, Austria 1 Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Germany 2 ITC-irst, via Sommarive 18, 38050 POVO, Trento, Italy 3... more
Atominstitut der Österreichischen Universitäten, TU Wien, Stadionallee 2, A 1020 Vienna, Austria 1 Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Germany 2 ITC-irst, via Sommarive 18, 38050 POVO, Trento, Italy 3 Inst. of Inorganic and applied Chemistry, 3 EÖTVÖS Univ , Budapest, Hungary 4 Hamburger Synchrotronstrahlungslabor at DESY, Notkestrasse 85, D 22607 Hamburg, Germany
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Since most micro-spectrometers are operated in air, up to now only mapping of medium and higher Z elements was possible with micro X-ray fluorescence analysis (µ-XRF). Though for some applications (e.g.: biological- and geological... more
Since most micro-spectrometers are operated in air, up to now only mapping of medium and higher Z elements was possible with micro X-ray fluorescence analysis (µ-XRF). Though for some applications (e.g.: biological- and geological samples, samples from art and archeology) the extension to light elements is of great interest. Therefore µ -XRF measurements using a polycapillary lens mounted inside a vacuum chamber have been performed. X-rays from a 2kW high power diffraction tubes (Mo and Cr anode) as well as from a low power 50 W Pd-anode tube were focused by means of the polycapillary X-ray optics. The polycapillary adjustment was performed with a combination of an X/Y stage and a gimbal allowing 3 translation and 2 rotation movements. With this setup it was possible to produce an X-ray spot of about 40µm in diameter at the sample surface. Sample motion is performed by an x-y-z-micrometer driven stage PC controlled. The position dependent fluorescence signal was collected by a Pelti...
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Inorganic arsenic species in ambient particulate matter (PM10 and PM2.5) have been determined in an urban area, in the vicinity of a metallurgical industrial plant.
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One of the main threats to human health from heavy metals is associated with the exposure to lead (Pb). In vivo X-ray fluorescence analysis (XRF) of human bone is a widely used technique to determine the total Pb body burden. The... more
One of the main threats to human health from heavy metals is associated with the exposure to lead (Pb). In vivo X-ray fluorescence analysis (XRF) of human bone is a widely used technique to determine the total Pb body burden. The intention of this work was to study the feasibility of in vivo L-shell XRF measurements of Pb in bone using X-ray tubes as excitation sources. Parameter studies using direct tube excitation with various anode materials (Mo and W) and filters as well as different secondary targets and low-Z polarizers were performed with regard to the lowest limits of detection (LLD) achievable for Pb in bone matrix. A breakthrough for the development of a portable spectrometer was achieved by using an air-cooled low-power (50 W) Pd anode X-ray tube, Mo secondary target, and a Peltier-cooled silicon drift detector. LLDs for Pb in bone were determined from measurements on a plaster-of-paris standard without overlying tissue equivalent material and found to be around 0.6 μg∕g.
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As Grazing Incidence X-ray Fluorescence (GIXRF) analysis does not provide unambiguous results for the characterization of nanometre layers as well as nanometre depth profiles of implants in silicon wafers by its own, the approach of... more
As Grazing Incidence X-ray Fluorescence (GIXRF) analysis does not provide unambiguous results for the characterization of nanometre layers as well as nanometre depth profiles of implants in silicon wafers by its own, the approach of providing additional information using the signal from X-ray Reflectivity (XRR) was tested. As GIXRF already uses an X-ray beam impinging under grazing incidence and the variation of the angle of incidence, a GIXRF spectrometer was adapted with an XRR unit to obtain data from the angle dependent fluorescence radiation as well as data from the reflected beam. A θ-2θ goniometer was simulated by combining a translation and tilt movement of a Silicon Drift detector, which allows detecting the reflected beam over 5 orders of magnitude. HfO2 layers as well as As implants in Silicon wafers in the nanometre range were characterized using this new setup. A just recently published combined evaluation approach was used for data evaluation.
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The 'Analytical Network for Nanotech' is a European analytical infrastructure supporting the development of micro- and nano-technologies. High quality research requires comparability of results when analytical... more
The 'Analytical Network for Nanotech' is a European analytical infrastructure supporting the development of micro- and nano-technologies. High quality research requires comparability of results when analytical methodologies are supplied by different sources. This is a requirement of quality controlled industries, too. Inorganic contamination capabilities of the joint laboratory are Total Reflection X-Ray Fluorescence (TXRF) using Synchrotron Radiation (SR) or X-ray tubes, Vapor Phase Decomposition (VPD) and subsequent Graphite Furnace Atomic Absorption Spectroscopy (GF-AAS) or Inductively Coupled Plasma Mass Spectrometry (ICPMS), and Time of Flight Secondary Ion Mass Spectrometry (ToF SIMS). Discrepancies of results from different tools using TXRF for detection of metal contamination on silicon wafer surfaces were observed during different round robin using spin coated silicon wafers and deposited point like contamination. The results were validated using GF-AAS and ICPMS. The impact of the (reference) sample used for calibration on the evaluated measurement was confirmed. Furthermore, measurement geometries, substrate orientation and reliability of the angle of incidence are crucial for the comparability of the results of the TXRF systems.
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ABSTRACT Total Reflection X-ray Fluorescence analysis (TXRF) is widely used in semiconductor industry for the analysis of silicon wafer surfaces. Typically an external standard is used for the calibration of the spectrometer. This is... more
ABSTRACT Total Reflection X-ray Fluorescence analysis (TXRF) is widely used in semiconductor industry for the analysis of silicon wafer surfaces. Typically an external standard is used for the calibration of the spectrometer. This is sensitive to errors in quantification. For small sample amounts the thin film approximation is valid, absorption effects of the exciting and the detected radiation are neglected and the relation between sample amount and fluorescence intensity is linear. For higher total sample amounts deviations from linearity have been observed (saturation effect). These deviations are one of the difficulties for external standard quantification.A theoretical determination of the ideal TXRF sample shape is content of the presented work with the aim to improve the calibration process and therefore the quantification.The fluorescence intensity emitted by different theoretical sample shapes was calculated, whereby several parameters have been varied (excitation energy, density, diameter/height ratio of the sample). It was investigated which sample shape leads to the highest fluorescence intensity and exhibits the lowest saturation effect. The comparison of the different sample shapes showed that the ring shape matches the ideal TXRF sample shape best.
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ABSTRACT A nanoliter droplet deposition unit was developed and characterized for application of sample preparation in TXRF. The droplets produced on quartz reflectors as well as on wafers show a good reproducibility, also the accuracy of... more
ABSTRACT A nanoliter droplet deposition unit was developed and characterized for application of sample preparation in TXRF. The droplets produced on quartz reflectors as well as on wafers show a good reproducibility, also the accuracy of the pipetted volume could be proved by a quantitative TXRF analysis using an external standard. The samples were found to be independent of rotation of the sample carrier. Angle scans showed droplet residue behavior, and the fluorescence signal is relatively invariant of the angle of incidence below the critical angle, which is useful for producing standards for external calibration for semiconductor surface contamination measurements by TXRF. Further it could be demonstrated that the nanoliter deposition unit is perfectly able to produce patterns of samples for applications like the quantification of aerosols collected by impactors.