Filtern
Dokumenttyp
- Zeitschriftenartikel (30)
- Vortrag (21)
- Posterpräsentation (2)
- Buchkapitel (1)
- Sonstiges (1)
Schlagworte
- Synchrotron (30)
- BAMline (26)
- XRF (18)
- Gold (7)
- Machine learning (7)
- XANES (7)
- Bayesian Statistics (5)
- Machine Learning (5)
- Gaussian process (4)
- Neural network (4)
- Artificial Inelligence (3)
- Bayesian Optimization (3)
- EXAFS (3)
- X-ray absorption spectroscopy (3)
- Alkali-activated materials (2)
- Artificial intelligence (2)
- CXC (2)
- Coded Aperture (2)
- Corrosion (2)
- D2XRF (2)
- Imaging (2)
- MIC (2)
- Microbially induced corrosion (2)
- TXRF (2)
- Time-resolved (2)
- VRFB (2)
- X-ray fluorescence (2)
- X-ray fluorescence spectroscopy (2)
- Absorption spectrometry (1)
- Acid resistance (1)
- Archaeometry (1)
- Archäometrie (1)
- Artificial Intelligence (1)
- Battery (1)
- Bayes (1)
- Bernstorf (1)
- Biogene Schwefelsäurekorrosion (1)
- Biogenic acid corrosion (1)
- Bone matrix (1)
- Calcium monofluoride (1)
- Capillary (1)
- Catalysis (1)
- Cobalt deposition (1)
- Cocoa (1)
- Coded aperture (1)
- Coded apertures (1)
- Color X-ray Camera (1)
- Compositional complex alloys (1)
- Crystallization (1)
- Cu catalysts (1)
- Debye-Waller parameter (1)
- Degradation mechanisms (1)
- Depth profile (1)
- Depth resolved XANES (1)
- Dipsersive XAS (1)
- Dispersive XAS (1)
- Egypt (1)
- Electrochemical CO2 conversion (1)
- Elemental mapping (1)
- Energy storage (1)
- Environmental impacts (1)
- Experimental setup (1)
- Extended X-ray absorption fine structure (1)
- Farbenlehre (1)
- GE-XANES (1)
- Gaussian Process (1)
- Gilding (1)
- Goethe (1)
- Graphite furnace (1)
- Grazin exit XANES (1)
- HR-CS-MAS (1)
- Handheld (1)
- Hazardous substances (1)
- High-entropy alloys (1)
- High-resolution synchrotron XRF (1)
- Histology (1)
- ICP-OES (1)
- Image reconstruction (1)
- Implant material (1)
- In situ (1)
- In situ studies (1)
- In-situ (1)
- Iterative reconstruction (1)
- Künstliche Intelligenz (1)
- Laterally-resolved (1)
- Macrophagen (1)
- Maia detector (1)
- Mechanochemistry (1)
- MicroXRF (1)
- Nafion 117 (1)
- Nanoparticle (1)
- Nanoparticles (1)
- Natural language processing (1)
- Near edge X-ray absorption fine structure spectroscopy (1)
- Nebra (1)
- Neural Network (1)
- Neural networks (1)
- Nondestructive testing techniques (1)
- Normung (1)
- Oxidation (1)
- PVDF-Based membrane (1)
- PVDF-based membrane (1)
- Prisma (1)
- Refractory alloys (1)
- Roadmap (1)
- Röntgenfluoreszenz (1)
- Slags (1)
- Structure analysis (1)
- Sulfidation (1)
- Synchrotron studies (1)
- Tattoo inks (1)
- Tesserae (1)
- Toxic metals (1)
- UV/VIS (1)
- Vanadium redox flow battery (1)
- Vanadium speciation (1)
- X-Ray Fluorescence (1)
- X-ray absorption fine structure (1)
- X-ray fluorescence imaging (1)
- X-ray spectroscopy (1)
- Xerogel (1)
- ZIF-8 (1)
- Zirconium (1)
- confocal (1)
Organisationseinheit der BAM
- 6 Materialchemie (55) (entfernen)
Paper des Monats
- ja (1)
Eingeladener Vortrag
- nein (21)
In this work, we describe the use of artificial neural networks for the quantification of X-ray fluorescence measurements. The training data were generated using Monte Carlo simulation, which avoided the use of adapted reference materials. The extension of the available data set by means of an ANN to generate additional data was demonstrated. Particular emphasis was put on the comparability of simulated and experimental data and how the influence of deviations can be reduced. The search for the optimal hyperparameter, manual and automatic, is also described. For the presented case, we were able to train a network with a mean absolute error of 0.1 weight percent for the synthetic data and 0.7 weight percent for a set of experimental data obtained with certified reference materials.
Increasing numbers of implant revisions are a current clinical issue. Interactions of the endoprosthesis biomaterial with the body affect implantation time by wear processes, i.e. corrosion and abrasion. Previously, cobalt-chrome implants were shown to cause high levels of cobalt ions being deposited in the bone matrix. To determine a poten- tial functional role of these ions on bone homeostasis, we have developed a non-destructive dual analysis of highly sensitive elemental analysis by synchrotron XRF directly in undecalcified histological bone thin sections (4 μm). In this study, samples from 28 bone samples from hip endoprosthesis carriers (Surface Replacement Arthroplasty, metal-on-metal bearing) with an implant lifetime of 17–1750 days were used. Results were compared to age- matched control specimens. The histological analysis identified areas of bone cell activity and assigned them for XRF measurements. Co-Cr wear particles were identified in the bone marrow. In addition, Co ions were highly enriched in the mineralized bone matrix. The cobalt deposits were not homogeneously distributed, and areas of high signal intensity were identified. Co was distinctly deposited in the newly formed osteoid layer, but also within deeper layers of the bone matrix, whereby the Co concentration increased with higher degrees of bone matrix mineralization. In the current study, we determined cobalt accumulations in the bone matrix and showed for the first time via synchrotron XRF with a high spatial resolution direct on histological slides, that cobalt deposits in the mineralized bone matrix in a mineral-specific way that is dependent upon the implant lifetime.
Enhancing efficiency at bamline: employing data science and machine learning for x-ray research
(2023)
This talk discusses how data science and machine learning techniques are being applied at the BAM Federal Institute for Materials Research and Testing to enhance efficiency and automation at the BAMLine synchrotron facility. The methods presented include Gaussian processes and Bayesian optimization for beamline adjustment and optimization of X-ray measurements. These statistical techniques allow automated alignment of beamline components and active learning scanning to reduce measurement time.
Additional machine learning methods covered are neural networks for quantification of X-ray fluorescence (XRF) data and decoding coded apertures.
This contribution provides an overview of the BAMline synchrotron radiation beamline, which specializes in hard X-ray spectroscopy techniques for materials research. The BAMline offers X-ray absorption spectroscopy (XAS), x-ray fluorescence spectroscopy (XRF), and tomography to study materials' electronic structure, chemical composition, and structure. Key capabilities include standard and dispersive XAS for electronic structure, micro-XRF for elemental mapping, coded aperture imaging, and depth-resolved grazing exit XAS. The BAMline enables in situ characterization during materials synthesis and functions for energy, catalysis, corrosion, biology, and cultural heritage applications.
Ongoing developments like the implementation of machine learning techniques for experiment optimization and data analysis will be discussed. For instance, Bayesian optimization is being used to improve beamline alignment and scanning. An outlook to the future, where the BAMline will continue pioneering dynamic and multi-scale characterization, aided by advanced data science methods, to provide unique insights into materials research, will be given.
X-ray fluorescence imaging is a well-established tool in materials characterization. In this work, we present the adaption of coded aperture imaging to full-field X-ray fluorescence imaging at the synchrotron. Coded aperture imaging has its origins in astrophysics, and has several advantages: Coded apertures are relatively easy to fabricate, achromatic, allow a high photon throughput, and high angular acceptance. Coded aperture imaging is a two-step-process, consisting of the measurement process and a reconstruction step. Different programs have been written, for the raytracing/forward projection and the reconstruction. Experiments with coded aperture in combination with a Color X-ray Camera and an energy-dispersive area detector, have been conducted at the BAMline. Measured samples were successfully reconstructed, and gave a 9.1-fold increase in count rate compared to a polycapillary optic.
Imaging with X-rays is a challenging field, due to the optical properties of X-rays. The fabrication of appropriate optics is usually expensive and requires an elaborate manufacturing process. One simpler and less expensive possibility of imaging high energy radiation is coded aperture imaging, a technique well established in astrophysics and also used in nuclear medicine or radiation detection, e.g., for nuclear decommissioning. Our aim is to adapt coded aperture imaging for X-ray fluorescence spectroscopy in the nearfield. In this work we show theoretical considerations and preliminary simulations of Image formation through a coded aperture and three different reconstruction methods to prepare the experiments. We used a new mask based on an inverted modified uniformly redundant array (MURA) that could be used for the construction of a decoding mask for all investigated geometrical arrangements.
The most commonly used reconstruction method, convoluting the detected image with a Decoding mask, does not always deliver satisfactory results. This is more noticeable for small distances between the object, mask and detector. Hence, we developed two new reconstruction methods, one based on iterative algebraic optimization and another one based on a genetic algorithm. Both show good performance even in those cases where the convolution method fails. This provides a basis for further investigations of the ideal parameters for near field coded aperture imaging and refinements of the algorithms. We performed first measurements with a coded aperture at the BAMline at BESSY II and could successfully reconstruct a test object from the obtained recorded images.
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. Der Fund von Bernstorf wird ausführlich diskutiert.
Synchrotron radiation X-ray fluorescence spectroscopy, in conjunction with atomic absorption and Raman spectroscopy, was used to analyze a set of top brand tattoo inks to investigate the presence of toxic elements and hazardous substances. The Cr, Cu, and Pb contents were found to be above the maximum allowed levels established by the Council of Europe through the resolution ResAP(2008)1 on requirements and criteria for the safety of tattoos and permanent makeup. Raman analysis has revealed the presence of a set of prohibited substances mentioned in ResAP(2008)1, among which are the pigments Blue 15, Green 7, and Violet 23. Other pigments that were identified in white, black, red, and yellow inks are the Pigment White 6, Carbon Black, Pigment Red 8, and a diazo yellow, respectively. The present results show the importance of regulating tattoo ink composition.
To gain insight into the possible origin of the gold used in the production of tesserae containing gold leaf less than 0.5 μm thick placed between two layers of glass, we propose a non-destructive synchrotron radiation (SR) XRF protocol based on sequential analysis under optimised analytical conditions. Using this protocol, trace element analysis is achieved with detection limits of 1–6 mg/kg. As Pt and Au have adjacent fluorescence energies, we tested the most challenging situation, when Pt is present in very low concentrations in gold. Data obtained by double-dispersive XRF (D2XRF) and μXRF for fourth–ninth-century mosaics decorating nine Eastern and Western religious buildings show that the Eastern and Western tesserae are made from different alloys.
However, these alloys are identical to those used to make gold leaf for gilding, because plastic deformation requires the use of gold alloys with high ductility and malleability. Although trace element composition of gold used in the concerned period is only available for coins, by comparing the amounts of Pt contained in the tesserae and in the coins we show that Roman tesserae are made from Roman gold, as described in the documentary sources. We observe for the Byzantine period the use of a Byzantine gold and of gold supposedly from different stages of recycling, and we suggest the use of Umayyad and Abbasid gold for the production of Islamic tesserae.
Our aim is to develop a simple and inexpensive method for full field X-ray fluorescence imaging.We combine an energydispersive array detector with a coded aperture to obtain high resolut ion images. To obtain the information from the recorded image a reconstruction step is necessary. The reconstruction methods we have developed, were tested on simulated data and then applied to experimental data. The first tests were carried out at the BAMline @BESSY II. This method enables the simultaneous detection of multiple elements,which is important e.g. in the field of catalysis.