Article

A New 3D Micro X-Ray Fluorescence Analysis Set-Up – First Archaeometric Applications

Article

A New 3D Micro X-Ray Fluorescence Analysis Set-Up – First Archaeometric Applications

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Abstract

A new 3D micro X-ray fluorescence (micro-XRF) analysis method based on a confocal X-ray set-up is presented. The capabilities of this new method are evaluated and illustrated with depth sensitive investigations of paint layers in ancient Indian Mughal miniatures. Successive paint layers could be distinguished non-destructively with a depth resolution of about 10 μm. Major and minor elements are detectable and can be discriminated in different layers. New light could be shed on ancient painting techniques and materials with this new 3D micro-XRF set-up.

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... La CXRF qui est parfois désignée sous le terme de "microscopie de fluorescence de rayons X confocal" ("confocal x-ray fluorescence microscopy") [11] ne doit pas être confondue avec la microscopie confocale brevetée en 1957 qui est une microscopie photonique [12][13][14]. Plus souvent, le nom utilisé pour désigner la CXRF souligne la capacité 3D de la technique, comme par exemple "3D micro-X-ray fluorescence" [15] ou "confocal 3D XRF" [16]. Les acronymes tels que 3D-XRF ne seront pas utilisés ici parce qu'ils résultent d'un abus de langage. ...
... La micro-fluorescence de rayons X en mode confocal est une technique non-invasive qui peut fournir des informations en profondeur sur la composition élémentaire et qui a montré son intérêt dans l'étude des structures stratifiées de l'ordre du micron [20,[23][24][25][26]. Au cours des deux dernières décennies, la CXRF a étendu le potentiel de la technique connue sous le nom de micro-fluorescence de rayons X (μ-XRF) au profilage en profondeur de matériaux multicouches [4,5,7,15]. La méthode μ-XRF classique utilise en général une lentille polycapillaire de rayons X placée à la sortie d'un tube de microfocalisation de rayons X. ...
... La CXRF découle historiquement du développement de la spectroscopie de fluorescence de rayons X en mode confocal induite par une source de rayonnement synchrotron. Cette technique est très souvent désignée par les mêmes dénominations et sigles que la CXRF dans la littérature [11,15,20,[37][38][39][40][41][42][43][44][45][46]. Cet usage aléatoire créé une confusion qui empêche toute différenciation claire entre les deux techniques. ...
... La CXRF qui est parfois désignée sous le terme de « microscopie de fluorescence de rayons X confocal » (« confocal x-ray fluorescence microscopy ») [11] ne doit pas être confondue avec la microscopie confocale brevetée en 1957 qui est une microscopie photonique [12][13][14]. Plus souvent, le nom utilisé pour désigner la CXRF souligne la capacité 3D de la technique, comme par exemple « 3D micro-X-ray fluorescence » [15], ou « confocal 3D XRF » [16]. Les acronymes tels que 3D-XRF ne seront pas utilisés ici parce qu'ils résultent d'un abus de langage. ...
... La micro-fluorescence de rayons x en mode confocal est une technique non-invasive qui peut fournir des informations en profondeur sur la composition élémentaire et qui a montré son intérêt dans l'étude des structures stratifiées de l'ordre du micron [20,[23][24][25][26]. Au cours des deux dernières décennies, la CXRF a étendu le potentiel de la technique connue sous le nom de micro-fluorescence de rayons X (µ-XRF) au profilage en profondeur de matériaux multicouches [4,5,7,15]. La méthode µ-XRF classique utilise en général une lentille polycapillaire de rayons X placée à la sortie d'un tube de microfocalisation de rayons X. ...
... La CXRF découle historiquement du développement de la spectroscopie de fluorescence de rayons x en mode confocal induite par une source de rayonnement synchrotron. Cette technique est très souvent désignée par les mêmes dénominations et sigles que la CXRF dans la littérature [11,15,20,[37][38][39][40][41][42][43][44][45][46]. Cet usage aléatoire créé une confusion qui empêche toute différenciation claire entre les deux techniques. ...
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La micro-fluorescence de rayons x en mode confocal (CXRF) est d’un intérêt considérable pour les sciences du patrimoine en raison de sa capacité à fournir des informations résolues spatialement sur la composition chimique du matériel analysé de manière non-invasive. Le défi consiste à déterminer la séquence stratigraphique de matériaux multicouches et leur composition chimique sans prélèvement. Les informations stratigraphiques sont en général obtenues en utilisant des techniques classiques micro-invasives et/ou micro-destructives. La technique la plus répandue consiste en l’analyse de microéchantillons par spectrométrie de rayons x couplée à la microscopie électronique à balayage (SEM-EDX). Cependant, les prélèvements ne sont pas toujours possibles sur des oeuvres patrimoniales.
... E. Sadeghi Meresht et al. determined the failure mechanisms of a gas transmission steel pipeline based on available documents and metallographic studies [6]. Among the X-ray methodologies, 3D-XRF enables analysis to a greater depth (~50-1000 μm) of samples than other surface analysis tools [8][9][10][11][12]. Therefore, in this paper, we attempted to use 3D-XRF to analyze oil pipeline fragment samples in depth. ...
... A confocal 3D-XRF spectrometer is an important analysis tool in depth tests [8,11,[13][14][15][16][17]. The confocal volume can be obtained using two X-ray optics; in our 3D-XRF, one is a polycapillary focusing X-ray lens (PFXRL) [18] at the excitation channel and the other is a polycapillary parallel X-ray lens (PPXRL) [19] at the detection channel [12]. ...
Article
Two paint fragments from an oil pipeline were analyzed with a confocal three-dimensional micro-X-ray fluorescence (3D-XRF) spectrometer. The depth distributions of iron (Fe), titanium (Ti) and zinc (Zn) metal elements were obtained based on confocal 3D-XRF analysis. The quantitative element results were obtained by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The corrosion process of the oil pipeline was investigated based on the experimental results, which provided information for designing an oil pipeline protection scheme.
... Three-dimensional micro-x-ray fluorescence (3D-XRF) has been an important analysis method in a large variety of fields [1] [2,3] since Kanngießer et al. constructed the first 3D-XRF setup in 2003. [4] The depth resolution of 3D-XRF is determined by its confocal volume in full width at half maximum (FWHM), which also represents the best resolution for 2D or 3D mapping of the device. Therefore, the size of the confocal volume of each 3D-XRF needs to be accurately calibrated. ...
... In practice, the value of d that most researchers can obtain is generally 10-30 µm. The confocal volume size for FWHM in synchrotron radiation 3D-XRF has been reported to be ∼ 10-40 µm, [4,[7][8][9][10][11][12] and that in desktop 3D-XRF has been reported to be ∼ 20-100 µm. [13][14][15] The essence of this classic method is to convolve D using a convolution kernel with thickness d. ...
Article
The measurement of the confocal volume of a confocal three-dimensional micro-x-ray fluorescence (3D-XRF) setup is a key step in the field of confocal 3D-XRF analysis. With the development of x-ray facilities and optical devices, 3D-XRF analysis with a micro confocal volume will create a great potential for 2D and 3D microstructural analysis and accurate quantitative analysis. However, the classic measurement method of scanning metal foils of a certain thickness leads to inaccuracy. A method for calibrating the confocal volume is proposed in this paper. The new method is based on the basic content of the textbook, and the theoretical results and the feasibility are given in detail for the 3D-XRF mono-chromatic x-ray condition and the poly-chromatic x-ray condition. We obtain a set of experimental confirmation using the poly-chromatic x-ray tube in the laboratory. It is proved that the sensitivity factor of the 3D-XRF can be directly and accurately obtained in a real calibration process.
... Compared to scanning XRF tomography, confocal XRF imaging uses x-ray focusing optics in both the excitation and the detection channels [3]. The overlap of the foci of both x-ray optics defines a micron-sized gauge volume in the sample, so that the elemental compositions of the sample can be mapped in both the lateral and the depth directions. ...
... The attenuation due to the air between the sample and the detector was estimated using the CXRO X-ray Database [8]. Fig. 4b shows a simulated confocal XRF image (RGB map) obtained using a focused pink beam with a size of 5 µm × 5 µm and a depth resolution of 20 µm, i.e. a voxel size of 5 (X) × 5 (Y) × 20 (Z) µm 3 . We assume the image is acquired by step-scan the sample in the XZ plane, with a step size of 5 µm in both X and Z directions. ...
... In order to address this limitation a confocal micro-XRF system (CXRF) capable of depth-resolved analysis of the chemical composition was used. Such set-ups have already demonstrated attractive potentials and capabilities on numerous works of art, especially paintings [7][8][9]. ...
... In the following section, the chemical maps of significant elements in the painting are shown (Figs. 5,6,7,8,9). The maps report the X-ray intensity of the most intense X-ray line of the element. ...
... For two or more overlapping layers, as in most of the paintings, the detector collects the X-rays from the whole analyzed depth and the material discrimination of different layer is very challenging except in some simple cases [15]. Recently, also a 3D μ-XRF spectrometer has been developed where the depth resolving capability is obtained by a confocal set-up with X-ray optics [16][17][18]. This technique has lower detection sensitivity than μ-XRF but, by applying complex algorithms, it can provide qualitative stratigraphic information about the detectable elements. ...
Article
Full-text available
With the aim to establish advantages and limitations of techniques commonly employed for material characterization of Cultural Heritage objects, we performed comparative measurements by LIBS, X-ray Fluorescence (XRF) and Particle Induced X-ray Emission (PIXE) on four typologies of materials. The samples include: 1) egg tempera pigments on gypsum ground; 2) oil paints on gypsum ground with light or dark imprimitura; 3) fragments of decorated glazed ceramic, and 4) ancient Roman coins. The optimal choice of an analytical instrument depends also on the sample type, its dimensions and transportability, and for these reasons our measurements involved two types of instruments per technique. The LIBS probing was done by a table-top instrument (on coins and ceramics) and by a stand-off system at distance of 9.5m (on pigments). The XRF measurements involved a laboratory micro-XRF system (on coins) and a portable instrument (on pigments and ceramics). The PIXE analyses were obtained by TOP-IMPLART accelerator at ENEA Frascati, using a low energy line that produces the proton beam with adjustable energy between 3 and 7 MeV (used for the pigments and ceramics), and by INFNLABEC system with proton energy of 3 MeV and complemented by Elastic Backscattering Spectrometry (EBS), for coin samples. Results relevant to quantitative analysis of major sample constituents, identification of trace components, and stratigraphy are reported and discussed for the examined typologies of samples.
... Micro-X-ray fluorescence (XRF) and XAS are powerful tools for spatially resolved structure analysis via sample mapping in the micrometre regime and have a large variety of fields of application such as environmental sciences, geology, life sciences and archeology. Importantly, the use of confocal X-ray optics, especially capillary optics (Kanngießer et al., 2003), provides a feasible route to analyze geological and cultural heritage samples with depth-resolved chemical speciation of elements (Vekemans et al., 2004;Lü hl et al., 2014;Kanngießer et al., 2012;Denecke et al., 2009). In confocal mode, a probing volume is created by the overlapped foci of two optics; the first one is placed in an excitation channel and the second in a detection channel. ...
Article
To illustrate the process of synchrotron radiation induced reduction of tetrachloroauric solutions, a confocal synchrotron radiation X-ray spectroscopy experiments system has been introduced to monitor the depth-resolved elemental Au distribution and chemical species during the Au reduction reaction. Combining the results from confocal X-ray spectroscopy with that from X-ray contrast imaging, the mechanism of synchrotron radiation induced Au reduction, along with the process of Au deposition, were proposed. These demonstrations provide novel avenues to spatially resolved analysis of in situ solution radiolysis.
... Due to wide applications of the radiation in human daily activities, safety demand is increasing for proper radiation shielding day by day. For this reason, researchers are trying to obtain new shielding materials for high energetic electromagnetic radiation such as X-and gamma rays which have been used in many different areas including radiology (Mettler Jr et al., 2008), elemental analysis ( Gürol et al., 2016;Kanngießer et al., 2003;Marguí et al., 2005), food irradiation (Farkas, 2006), industry (Hormes and Warner, 2012) and medicine (Reed, 2011) etc. ...
... The confocal three-dimensional micro-X-ray fluoroscope (3D-XRF) plays an important role in non-destructive tests [1][2][3][4][5][6][7][8][9][10][11][12]. The basic idea of the 3D-XRF was proposed by Gibson and Kumakhov [13]. ...
Article
Two samples of ancient Chinese coins were analyzed with a confocal three-dimensional micro-X-ray fluoroscope. The depth distributions of elemental iron (Fe), calcium (Ca) and copper (Cu) were obtained based on this non-destructive measurement method. One coin, named “Chongning Tongbao” was certified as genuine in accordance with the available archaeological data, whereas another coin, named “Zhenglong Yuanbao” was identified as a reproduction.
... For example, using a high flux density exceeding 10 13 photons s À1 mm À2 [e.g. at the ESRF ID22NI nanoprobe beamline using bent Kirkpatrick-Baez (KB) multi-layer mirrors], even a few thousand atoms of transition metals can be detected at a spatial resolution of $ 90 nm (Adams et al., 2011). The development of fast, new-generation array X-ray detection systems processing high count rates and coupled with on-the-fly scanning stages (Lombi et al., 2011), the use of external total reflection irradiation geometry (total-reflection X-ray fluorescence, TXRF) for surface-sensitive analysis (Streli et al., 2008;Meirer et al., 2010;Fittschen et al., 2016;Singh et al., 2017) and the application of polycapillary optics to allow depth-resolved and eventually three-dimensional elemental analysis (3D-mXRF) of structured materials (Kanngießer et al., 2003;Janssens et al., 2004) or of buried inclusions in diamonds have significantly improved the analytical merits and the importance of SR-XRF analysis in various applications of emerging interest. When SR-XRF analysis is applied at beamlines with suitable monochromators offering high energy resolution ( 10 À4 ) and spectral purity, the X-ray absorption fine-structure (XAFS) methodology offers additional unique information on the oxidation state, chemical environment and local symmetry of the sample constituent atoms. ...
Article
Full-text available
The International Atomic Energy Agency (IAEA) jointly with the Elettra Sincrotrone Trieste (EST) operates a multipurpose X-ray spectrometry endstation at the X-ray Fluorescence beamline (10.1L). The facility has been available to external users since the beginning of 2015 through the peer-review process of EST. Using this collaboration framework, the IAEA supports and promotes synchrotron-radiation-based research and training activities for various research groups from the IAEA Member States, especially those who have limited previous experience and resources to access a synchrotron radiation facility. This paper aims to provide a broad overview about various analytical capabilities, intrinsic features and performance figures of the IAEA X-ray spectrometry endstation through the measured results. The IAEA–EST endstation works with monochromatic X-rays in the energy range 3.7–14 keV for the Elettra storage ring operating at 2.0 or 2.4 GeVelectron energy. It offers a combination of different advanced analytical probes, e.g. X-ray reflectivity, X-ray absorption fine-structure measurements, grazing-incidence X-ray fluorescence measurements, using different excitation and detection geometries, and thereby supports a comprehensive characterization for different kinds of nanostructured and bulk materials.
... 3D XRF mapping is based either by pencil-shaped primary X-ray beams and reconstruction algorithms similar to the ones used in CT (i.e. SRXRF tomography) [78,79] or using specialized optics on both the X-ray source and detector (confocal XRF) [80,81]. ...
Article
This review summarizes the state-of-the-art synchrotron-based techniques for studying the environmental health effects of heavy metals exposure. Synchrotron radiation based X-ray fluorescence (SRXRF) is widely applied in quantification of metals in different biological and environmental samples. X-ray absorption spectrometry (XAS) is used for speciation of heavy metals. With high energy resolution fluorescence detected (HERFD) XAS, it is possible to study heavy metals in biological samples at realistic concentrations. The focused synchrotron-based X-ray is applied to image metals down to nm resolution at 2- or 3- dimension (2D or 3D). The combination of XAS with SRXRF can realize 2D or 3D spatial speciation, along with other techniques like scanning transmission X-ray microscopy (STXM) and full field XAS. The structure of metal-binding biomolecules can be characterized by Protein X-ray Diffraction (PX) and/or XAS, together with neutron scattering. The future aspects of multimode detection, new imaging methods, fast detector technologies and big data strategies in synchrotron-based techniques were also discussed.
... Confocal XFM provides an alternative approach to interrogation of specific subvolumes within a specimen to further disentangle the projected information. Confocal XFM uses a confocal optic to confine the field of view of the energy-dispersive detector so that the signal derives from only a small portion of the illuminated column (Kanngiesser et al., 2003). Confocal optics can be used for 3D 'tomographic' imaging within a specimen (by scanning the specimen through the confocal volume), or direct interrogation of a small subvolume within a specimen. ...
Article
Full-text available
Hyperaccumulators are attractive models for studying metal(loid) homeostasis, and probing the spatial distribution and coordination chemistry of metal(loid)s in their tissues is important for advancing our understanding of their ecophysiology. X-ray elemental mapping techniques are unique in providing in situ information, and with appropriate sample preparation offer results true to biological conditions of the living plant. The common platform of these techniques is a reliance on characteristic X-rays of elements present in a sample, excited either by electrons (scanning/transmission electron microscopy), protons (proton-induced X-ray emission) or X-rays (X-ray fluorescence microscopy). Elucidating the cellular and tissue-level distribution of metal(loid)s is inherently challenging and accurate X-ray analysis places strict demands on sample collection, preparation and analytical conditions, to avoid elemental redistribution, chemical modification or ultrastructural alterations. We compare the merits and limitations of the individual techniques, and focus on the optimal field of applications for inferring ecophysiological processes in hyperaccumulator plants. X-ray elemental mapping techniques can play a key role in answering questions at every level of metal(loid) homeostasis in plants, from the rhizosphere interface, to uptake pathways in the roots and shoots. Further improvements in technological capabilities offer exciting perspectives for the study of hyperaccumulator plants into the future.
... Compared to the traditional x-ray fluorescence (XRF) analysis technology, which can measure only the elemental distribution on the surface of a flat sample, confocal 3D-MXRF analysis technology can arbitrarily measure samples within a certain depth range. Many samples such as small animals and plants, ancient paintings, enamels, glassware, and porcelain have been tested using confocal 3D-MXRF analytical technology [3][4][5][6][7][8][9][10]. In these experiments, the range analyzed was a rectangular plane, but for some layered samples, many inner layers are not planar. ...
Article
Three-dimensional microfocus x-ray fluorescence technology has been used to determine surface topography. The surface scanning technique initially facilitated surface topography reconstruction of the sample. This paper demonstrates the improved performance of its infrastructure, including a higher-precision translation platform, an ultrabright microfocus x-ray source and a rewritten scanning algorithm, leading to a new scanning technology that can depict the surface topography of samples with complex internal structures. The improved scanning technology can analyze the metal element information of layers at different depths. This paper presents studies of the surface and depth of coins and porcelain bottles from ancient times using this technique.
... It presents several limitations, but is (one of the few) non-destructive movable method and will be used a lot in the future. The hold time of several tens of seconds requires long scans (about half an hour) for a single depth of profile, but is possible to obtain virtual 2D cross-sections or even 3D data cubes (Kanngießer et al., 2013) as was confirmed at a black drawing cat visualized behind a Vincent Van Gogh's paintings ‗'Daubigny's Garden'' (Nakanoa et al., 2016). ...
Article
Full-text available
Paintings, mostly due to deteriorations, are sometimes repainted, concealing in underlayers important features, dates, names and other information. Conservators are facing dilemmas as to whether to preserve these interventions and retrieve valuable hidden information, but in the last decades the evolution of spectroscopic techniques has contributed to such uncertainties. The current brief review explains the intentional repaint and presents the techniques used around the world to visualize the underpainting layers, and how these techniques have developed from a simple X-Ray radiography and an infrared (IR) photography to mobile devices with great imaging capabilities. Case studies include Byzantine icons and oil paintings.
... 3D XRF mapping is based either by pencil-shaped primary X-ray beams and reconstruction algorithms similar to the ones used in CT (i.e. SRXRF tomography) [78,79] or using specialized optics on both the X-ray source and detector (confocal XRF) [80,81]. ...
Article
This review summarizes the state-of-the-art synchrotron-based techniques for studying the environmental health effects of heavy metals exposure. Synchrotron radiation based X-ray fluorescence (SRXRF) is widely applied in quantification of metals in different biological and environmental samples. X-ray absorption spectrometry (XAS) is used for speciation of heavy metals. With high energy resolution fluorescence detected (HERFD) XAS, it is possible to study heavy metals in biological samples at realistic concentrations. The focused synchrotron-based X-ray is applied to image metals down to nm resolution at 2-or 3-dimension (2D or 3D). The combination of XAS with SRXRF can realize 2D or 3D spatial speciation, along with other techniques like scanning transmission X-ray microscopy (STXM) and full field XAS. The structure of metal-binding biomolecules can be characterized by Protein X-ray Diffraction (PX) and/or XAS, together with neutron scattering. The future aspects of multimode detection, new imaging methods, fast detector technologies and big data strategies in synchrotron-based techniques were also discussed.
... Nowadays X-ray spectroscopy is employed in almost every thinkable field of technology and research. To give just a few examples, applications range from fundamental research in chemistry [3][4][5][6][7][8], physics [9][10][11][12][13][14][15] and material science [16,17], to environmental research [18,19], architecture [20], art [19,21,22], archeology [19,[23][24][25] and industrial applications [19], to even forensics [19], security systems [26,27] and astronomy [28][29][30][31]. In a scientific context X-ray spectroscopy is also known as core-level-or core-spectroscopy [32,33] and it has become an essential tool for the study of a vast number of systems. ...
Article
Full-text available
X-ray spectroscopy is an important tool for scientific analysis. While the earliest demonstration experiments were realised in the laboratory, with the advent of synchrotron light sources most of the experiments shifted to large scale synchrotron facilities. In the recent past there is an increased interest to perform X-ray experiments also with in-house laboratory sources, to simplify access to X-ray absorption and X-ray emission spectroscopy, in particular for routine measurements. Here we summarise the recent developments and comment on the most representative example experiments in the field of in-house laboratory X-ray spectroscopy. We first give an introduction and some historic background on X-ray spectroscopy. This is followed by an overview of the detection techniques used for X-ray absorption and X-ray emission measurements. A short paragraph also puts related high energy resolution and resonant techniques into context, though they are not yet feasible in the laboratory. At the end of this section the opportunities using wavelength dispersive X-ray spectroscopy in the laboratory are discussed. Then we summarise the relevant details of the recent experimental laboratory setups split into two separate sections, one for the recent von Hamos setups, and one for the recent Johann/Johansson type setups. Following that, focussing on chemistry and catalysis, we then summarise some of the notable X-ray absorption and X-ray emission experiments and the results accomplished with in-house setups. In a third part we then discuss some applications of laboratory X-ray spectroscopy with a particular focus on chemistry and catalysis.
... die chemische Zusammensetzung kann nicht nur zerstörungsfrei orts-, sondern auch tiefenaufgelöst bestimmt werden. Dieser tiefensensitive 3D-Mikro-RFA Aufbau wurde erstmalig an der BAMline am Berliner Elektronenspeicherring realisiert [19,20] Gewissheit festgestellt werden, in denen es sich um Schriftzüge handelt, was bei bloßen An-und Unterstreichungen oder Kreuzen oft nicht möglich ist. Erste Messungen mittels RFA wurden an drei verschiedenen Notizbüchern durchgeführt. ...
Article
Summary Scientific analysis, especially the chemical composition, of artistic and cultural heritage objects reveals information, which cannot be gained from art historical investigations alone. The improvement of X-ray analytical method, like X-ray fluorescence (XRF) analysis and Particle-Induced X-ray Emission (PIXE) analysis, makes it possible to investigate even fragile and very precious objects non-destructively. In principle, two strategies are generally embarked: First, very sophisticated set-ups using particle accelerators or synchrotron-radiation sources for very sensitive or highly spatially-resolved and depth-sensitive analysis. Second, portable instrumentation for in-situ measurements at archaeological excavations, museums and collections. Highlights of investigated objects are limoges school enamels, manuscripts of Goethe and Schiller, the sceptre of Charlemagne, medieval metal objects, silverpoint drawings from the Renaissance, and Indian Mughal paintings.
... Considerably more drastic changes were observed for the parchment samples with ultramarine paint layer. In contrast to the unpainted sample, slight changes of the parchment morphology occured at the parchment surface even at a fluence of 1 µC/cm 2 (Fig. 4C,D). At higher beam fluences (4 and 10 µC/cm 2 ) the parchment has apparently completely lost its typical collagen fiber structure up to a depth of 100 µm (see areas outlined in red in Fig. 4F,H). ...
Article
Full-text available
Ion beam analysis plays an important role in cultural heritage (CH) studies as it offers a combination of simultaneous and complementary analytical techniques (PIXE/PIGE/RBS) and spatially resolved mapping functions. Despite being considered non-destructive, the potential risk of beam-induced modifications during analysis is increasingly discussed. This work focuses on the impact of proton beams on parchment, present in our CH in form of unique historical manuscripts. Parchment is one of the organic, protein-based CH materials believed to be the most susceptible to radiation-induced changes. Various modification patterns, observed on parchment cross-sections by optical and electron microscopy are reported: discoloration (yellowing), formation of cavities and denaturation of collagen fibers. Considerable modifications were detected up to 100 µm deep into the sample for beam fluences of 4 µC/cm ² and higher. The presence of ultramarine paint on the parchment surface appears to increase the harmful effects of proton radiation. Based on our results, a maximum radiation dose of 0.5 µC/cm ² can be considered as ‘safe boundary’ for 2.3 MeV PIXE analysis of parchment under the applied conditions.
... Since Kanngießer et al. built the first three-dimensional (3D) confocal device [1], this analysis technology has been widely used in many fields [2][3][4][5][6]. The theoretical basis of 3D confocal x-ray fluorescence analysis (3DXRF) is the theory of irradiating material attenuation and enhancement effects [7]. ...
Article
Three-dimensional (3D) confocal x-ray fluorescence analysis technology is widely used, but the quantitative analysis of elemental spatial distributions of solid samples is complicated. This paper explores a quantitative analysis method that can be applied to solid samples. Fluorescence spectra of liquid samples are obtained on a 3D confocal x-ray fluorescence spectrometer. Curves are plotted showing the relationships between the fluorescence count intensity and the mass percentage of metal ions, and the respective fitting-curve equations are determined according to the curve morphology. Fluorescence intensity as a function of the mass percentage and depth position is derived from the samples for a particular acquisition time. These data play a potential role in the subsequent quantitative analysis of unknown mass percentages of solid samples.
... However, in confocal micro-XRF (C-M-XRF), it is possible to obtain the elemental information from only the confocal volume by arranging the polycapillary lenses in front of both the X-ray generator and detector, as illustrated in Fig. 1(b). In the early 2000s, the C-M-XRF technique was applied to desktop-type devices 6 and since then, several studies on C-M-XRF have been conducted and reported [7][8][9][10][11] . Desktop-type C-M-XRF devices enable three-dimensional (3D) elemental analysis. ...
Article
Micro X-ray fluorescence (XRF) enables the non-destructive analysis of particle contamination. In this study, we compared the detection sensitivities and the LLD (lower limit of detection) values of micro-metallic particle contaminations on the plastic detected by micro-XRF and confocal micro-XRF. First, to verify the effectiveness of the confocal micro-XRF, we compared the intensities of different shaping copper samples (plate, thin film and particle). The results demonstrated that confocal micro-XRF is more effective than micro-XRF for the detection of micro particles. Second, to compare the SN ratios of different X-ray energies, several micro-metallic particles (Si, Fe, and Cu) set on an acrylic plate were measured by micro-XRF and confocal micro-XRF. It was found that the SN ratios of the confocal micro-XRF when measuring the Si, Fe, and Cu particles were improved to be approximately 14.6, 21.9, and 43.5-times those of the micro-XRF, respectively. It was determined that confocal micro-XRF is more effective for micro-metallic particles in the higher energy region.
... This arrangement makes it possible to perform depth resolved measurements by overlapping the foci of the primary and secondary optics resulting in a voxel. [5][6][7] Typical μXRF spectrometers in the lab use a polychromatic source, i.e., a low-power (20 W-50 W) tube without a monochromator, and a polycapillary as a focusing optic. As the focusing properties of a polycapillary rely on the total reflection of x rays at the capillary walls, and the critical angle of total reflection changes with the energy, the size of the primary spot is ill-defined for a polychromatic beam. ...
Article
Confocal micro-x-ray fluorescence (μXRF) is a powerful tool to analyze the spatial distribution of major, minor, and trace elements in three dimensions. Typical (confocal) μXRF measurements in the lab use polychromatic excitation, complicating quantification and fundamental parameter-based corrections and furthermore deteriorating peak-to-background ratios due to scattered bremsstrahlung. The goal for the new setup was to remedy these problems, without sacrificing spatial resolution, and keep it flexible for different excitation energies and transportation to other sources. The source assembly consists of a water-cooled fine-focus x-ray diffraction tube and a parallel beam-mirror, which produces a quasi-parallel, monochromatic beam. The presented results were obtained using a 2 kW molybdenum tube and a mirror for Mo-Kα. The confocal setup itself consists of two polycapillary half-lenses, one for the source side and the other for the detector side, where a 50 mm² silicon drift detector is mounted. Both polycapillaries have a focus size of ∼15 μm for Mo-Kα. The second polycapillary can also be exchanged for a custom-designed collimator in order to perform non-confocal μXRF. Details of the technical setup and results from technical and biological samples are presented. Detection limits for selected elements from Ca to Pb in the confocal and non-confocal mode were established (e.g., 1 μg/g non-confocal and 20 μg/g confocal for As) using the NIST standard reference materials (SRMs) 621 and 1412. Furthermore, the results of the measurements of SRM 621 were evaluated using the fundamental parameter based quantification software ATI-QUANT. The results are compared with the certified values and generally are in good agreement.
... More important, they limit the number of recorded photons, so that CXRF investigations are in practice often limited to a single depth profile and do not allow for the acquisition of 3D volumes. The capabilities of CXRF for the investigation of paint layers have been already demonstrated in 2003 [148]. ...
Article
This paper provides an overview over the application of scanning macro-XRF with mobile instruments for the investigation of historical paintings. The method is compared to synchrotron based macro-XRF imaging and Neutron Activation Auto-Radiography. Full-Field XRF imaging instruments, a potential future alternative to scanning macro-XRF, and confocal XRF, providing complementary depth profiles and developing into a 3D imaging technique itself, are described with the focus on investigations of historical paintings. Recent developments of X-ray radiography are presented and the investigation of cultural heritage objects other than paintings by MA-XRF is summarized. In parallel to XRF, hyperspectral imaging in the visible and range has developed into a technique with comparable capabilities, providing insight in chemical compounds, where XRF imaging identifies the distribution of elements. Due to the complementary nature of these techniques the latter is summarized. Further, progress and state of the art in data evaluation for spectroscopic imaging is discussed. In general it could be observed that technical capabilities in MA-XRF and hyperspectral imaging have reached a plateau and that with the availability of commercial instruments the focus of recent studies has shifted from the development of methods to applications of the instruments. Further, that while simple instruments are easily available with medium budgets only few groups have high-end instrumentation available, bought or in-house built.
Article
A confocal fluorescence endstation for depth-resolved micro-X-ray absorption spectroscopy is described. A polycapillary half-lens defines the incident beam path and a second polycapillary half-lens at 90° defines the probe sample volume. An automatic alignment program based on an evolutionary algorithm is employed to make the alignment procedure efficient. This depth-resolved system was examined on a general X-ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility. Sacrificial red glaze (AD 1368–1644) china was studied to show the capability of the instrument. As a mobile endstation to be applied on multiple beamlines, the confocal system can improve the function and flexibility of general XAS beamlines, and extend their capabilities to a wider user community.
Article
Novel confocal X-ray fluorescence (XRF) spectrometer was designed and constructed for 3D analysis of elementary composition in the surface layer of spatially extended objects having unlimited chemical composition and geometrical shape. The main elements of the XRF device were mounted on a moving frame of a commercial 3D printer. The XRF unit consists of a silicon drift detector and a low-power transmission-type X-ray tube. Both the excitation and secondary X-ray beams were formed and regulated by simple collimator systems in order to create a macro confocal measuring setup. The spatial accuracy of the mechanical stages of the 3D printer achieved was less than 5 μm at 100-μm step-size. The diameter of the focal spot of the confocal measuring arrangement was between 1.5 and 2.0 mm. The alignment of the excitation and secondary X-ray beams and the selection of the measuring spot on the sample surface were ensured by two laser beams and a digital microscope for visualization of the irradiated spot. The elements of the optical system together with the XRF spectrometer were mounted on the horizontal arm of the 3D printer, which mechanical design is capable of synchronized moving the full spectroscopic device within vertical directions. Analytical capability and the 3D spatial resolution of the confocal spectrometer were determined. Copyright
Chapter
Metallomics, focusing on the global and systematic understanding of the metal uptake, trafficking, role, and excretion in biological systems, has attracted more and more attention. Metal-related nanomaterials, including metallic and metal-containing nanomaterials, have unique properties compared to their macroscale counterparts and therefore require special attention. The absorption, distribution, metabolism, excretion (ADME) behavior of metal-related nanomaterials in the biological systems is influenced by their physicochemical properties, the exposure route, and the microenvironment of the deposition site. Nanomaterials not only may interact directly or indirectly with genes, proteins, and other molecules to bring genotoxicity, immunotoxicity, DNA damage, and cytotoxicity but may also stimulate the immune responses, circumvent tumor resistance, and inhibit tumor metastasis. Because of their advantages of absolute quantification, high sensitivity, excellent accuracy and precision, low matrix effects, and nondestructiveness, nuclear and related analytical techniques have been playing important roles in the study of metallomics and nanometallomics. In this chapter, we present a comprehensive overview of nuclear and related analytical techniques applied to the quantification of metallome and nanometallome, the biodistribution, bioaccumulation, and transformation of metallome and nanometallome in vivo, and the structural analysis. Besides, metallomics and nanometallomics need to cooperate with other -omics, like genomics, proteomics, and metabolomics, to obtain the knowledge of underlying mechanisms and therefore to improve the application performance and to reduce the potential risk of metallome and nanometallome.
Article
The Herakles 3D X-ray scanner is a unique and versatile instrument developed at Ghent University integrating X-ray µCT, XRF tomography and confocal XRF analysis in a single laboratory instrument. The three techniques are placed side by side on a large table in order to maximize the space available for each technique. This means no compromises were needed in order to fit the components close together. Hence, each end station of Herakles (µCT, XRF-CT and confocal XRF) represents the state-of-the-art of currently available laboratory techniques. The concept of the Herakles scanner relies strongly on its high precision (around 100 nm) air-bearing motor system to connect the different techniques, allowing measurements at the three end stations while retaining the coordinate system. In-house developed control and analysis software further ensures a smooth integration of the techniques. Case studies on a Cu test pattern, a Daphnia magna model organism and a perlite biocatalyst support material demonstrate the attainable resolution of the instrument and the strength of combining these three complementary methodologies.
Article
We present a novel absorption correction approach for elemental distribution images obtained with a laboratory confocal micro X-ray fluorescence spectrometer. The procedure is suited especially for biological samples, as a constant dark matrix with a varying minor or trace element distribution is assumed. The constant absorption in the sample is extracted from depth dependent measurements. By using the concept of an effective excitation energy, depth-dependent and element-specific excitation energy values are calculated. For each voxel of a full 3D measurement, a correction is performed taking into account the actual number of voxels in the excitation and detection path. As proof of concept, the embryonic region of pearl millet seeds is investigated. Data are measured from the top and bottom side, resulting in a good agreement after the application of the absorption correction procedure. The distribution of elemental micronutrients is compared in seeds of two pearl millet genotypes. The corrected images illustrate different localization patterns of the micronutrient elements in pearl millet seed tissues.
Article
Quantitative nano-imaging of metal traces in a solid is a recent capability arising from the construction of hard X-ray nanoprobes dedicated to X-ray Fluorescence (XRF) imaging on upgraded third generation synchrotrons. Micrometer sample preparation valid for trace analysis is a fundamental part of the required developments to capitalize on the reduced Minimum Detection Limits. Practical guidelines lead us to propose a customized use of Focused Ion Beams (FIB) backed by state of the art Monte Carlo XRF modeling to initiate preparations of new samples and certified standards. The usefulness of these developments is illustrated by the first detection of Ni traces (4.57E+07 ± 3.2E+06 (7.1 %) at.μm⁻³) in a 3.35 Ga old microstructure of putative microbial origin from Barberton (South Africa). A list of feasibility checks provides a way of getting below 5 ppm MDLs for acquisition-times of 10 seconds with an analytical precision better than 10 %.
Article
The study presents the application of combined micro-Spatially Offset Raman Spectroscopy (micro-SORS) and confocal X-ray fluorescence (confocal XRF) to the non-destructive investigation of micrometer scale stratified painted systems. Micro-SORS can be applied in situations where a high turbidity of layers prevents the acquisition of conventional Raman signals from depth and in the presence of Raman scattering compounds, facilitating highly chemically specific (molecular) characterization of the layers. In contrast, confocal XRF provides elemental information on a well-defined volume at a given depth. In this study, selected specimens have been analysed with both methods; molecular and elemental data have been compared and integrated for a comprehensive characterization of the stratigraphy. This dual approach represents a new analytical modality in the area of Cultural Heritage and is also beneficial in areas where non-destructive interrogation of thin layers and films is required.
Chapter
Since its development in the 1970s (Hounsfield, Br J Radiol 46(552):1016–1022, 1973) [1], X-ray tomography has been used to study the three dimensional (3D) structure of nearly every type of material of interest to science, both in the laboratory (Elliott and Dover, J Microsc 126(2):211–213, 1982) [2] and at synchrotron facilities (Thompson et al., Nucl Instrum Methods Phys Res 222(1):319–323, 1984) [3]. The ability to nondestructively image internal structures is useful in the medical community for patient diagnosis. For this same reason, it is critical for understanding material structural morphology. X-ray tomography of static materials can generate a true 3D structure to map out content and distribution within materials including voids, cracks, inclusions, microstructure, and interfacial quality. This technology is even more useful when applying a time component and studying the changes in materials as they are subjected to non-equilibrium stimulations. For example, testing mechanical properties (e.g., compressive or tensile loading), thermal properties (e.g., melting or solidification), corrosion, or electrostatic responses, while simultaneously imaging the material in situ, can replicate real world conditions leading to an increase in the fundamental understanding of how materials react to these stimuli. Mechanical buckling in foams, migration of cracks in composite materials, progression of a solidification front during metal solidification, and the formation of sub-surface corrosion pits are just a few of the many applications of this technology. This chapter will outline the challenges of taking a series of radiographs while simultaneously stressing a material, and processing it to answer questions about material properties. The path is complex, highly user interactive, and the resulting quality of the processing at each step can greatly affect the accuracy and usefulness of the derived information. Understanding the current state-of-the-art is critical to informing the audience of what capabilities are available for materials studies, what the challenges are in processing these large data sets, and which developments can guide future experiments. For example, one particular challenge in this type of measurement is the need for a carefully designed experiment so that the requirements of 3D imaging are also met. Additionally, the rapid collection of many terabytes of data in just a few days leads to the required development of automated reconstruction, filtering, segmentation, visualization, and animation techniques. Finally, taking these qualitative images and acquiring quantitative metrics (e.g., morphological statistics), converting the high quality 3D images to meshes suitable for modeling, and coordinating the images to secondary measures (e.g., temperature, force response) has proven to be a significant challenge when a materials scientist ‘simply’ needs an understanding of how material processing affects its response to stimuli. This chapter will outline the types of in situ experiments and the large data challenges in extracting materials properties information.
Article
Confocal micro X-ray fluorescence spectroscopy (confocal micro-XRF) has recently become a significant instrumental method for analyses of cultural heritage as it provides depth-resolved information on elemental distribution of the investigated samples. This work describes results of confocal micro-XRF analyses of paint layers of two Bohemian panel paintings from the half of the 15th century that are part of the collections of the National Gallery in Prague. All the measurements were performed using a table top confocal micro-XRF setup designed at the Czech Technical University in Prague. A depth-profiling was used for investigation of red and blue paint layers in order to compare the composition and structure of the used pigments. Obtained results were compared with findings from the material survey on the sample taken from the painting Assumpta from Deštná (ca 1450, inv. no. O 724) to verify their origin in the same workshop. Confocal micro-XRF provides satisfactory data to specify the art workshop.
Chapter
Oil paint is a dynamic system that undergoes chemical alteration on several time and length scales. At the short term, curing reactions are necessary for oil to dry properly. At longer time scales, a wide variety of other chemical processes can negatively affect the visual appearance or mechanical properties of historical artistic paint systems. The development of chemical imaging methods capable of covering length scales continuously from the millimetric to micro- or even nanoscale is key in understanding the chemical composition of a painting and the historical changes thereof. Such imaging methods can help in assessing to which extent the original painting’s composition may have been modified by chemical degradation processes. Processes that occur in the highly heterogeneous mixtures of binders, pigments, additives, alteration products and possibly later repainting and restoration treatments. Establishing the precise biography of the painting contributes to evaluate its authenticity. New modalities and novel methods of microchemical imaging provide access to previously unexplored length scales, are capable of better differentiation between the various oil paint components (original composition or later addition), and allow performing faster analysis to produce higher definition images. In this review, we report on recent methodological developments and future prospects to determine oil paints composition using microchemical imaging at the micro- and nanoscale.KeywordsImagingSpectroscopyMicroscopyPaintPigments
Article
The study concerns the unique archaeological find of a silver jar lid, decorated using enamel technique. The find was made in South Moravia at Hradisko u Mušova, also known as Mušov-Burgstall, which is connected to the period of Marcomannic Wars (172-180 AD). At the moment of discovery, on the basis of art historical analysis, this unique artefact was dated into the reign of Emperor Augustus (27 BC – 14 AD). However, the used technique of enamel would be completely unique in Roman context for this period, and we have even discovered analogies in modern enamels recently. This item might have been lost in the Mušov-Burgstall region at the beginning of 20th century, when the first archaeological activities have started in this region. The artefact might also have been lost by a German or a Russian soldier, because some military operations of the end of the Second World War took place in this region. On the basis of the uniqueness of this item, we have started to deal with some questions concerning dating and manufacturing technology in a non-destructive manner using various X-ray fluorescence techniques.
Article
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We present a new approach to 3-dimensional chemical imaging based on X-ray computed micro tomography (CT), which enables the analysis of the internal elemental chemistry. The method uses a conventional laboratory-based CT scanner equipped with a semiconductor detector (CdTe). Based on the X-ray absorption spectra, elements in a sample can be distinguished by their specific K-edge energy. The capabilities and performance of this new approach are illustrated with different experiments, i.e. single pure element particle measurements , element differentiation in mixtures, and mineral differentiation in a natural rock sample. The results show that the method can distinguish elements with K-edges in the range of 20 to 160 keV, this corresponds to an element range from Ag to U. Furthermore, the spectral information allows a distinction between materials, which show little variation in contrast in the reconstructed CT image.
Article
X-ray fluorescence analysis is a frequently used analytical method in a number of areas for many decades, including the research of objects of cultural heritage. Especially in this area, the irreplaceable advantage is the fact that the measurement can be performed non-destructively and non-invasively on the examined object as a whole. It affects only a relatively thin layer at the surface of the object under investigation, nevertheless, this layer can have a complex structure (various coatings, gilding or other metallization, paint layers, etc.). Information about it can be a valuable contribution both to historical knowledge and to restoration work. During the development of the method, therefore, several procedures were elaborated to estimate the homogeneity or possible inhomogeneities of the investigated layer. In principle, the simplest one is to measure at different beam angles. However, this also changes the depth in the material into which the radiation penetrates. Without changing the measurement geometry, it is possible to use simultaneous detection of two different energy lines of the characteristic radiation of the investigated element (e.g., Kα and Kβ) and to evaluate the depth distribution on the basis of their ratio. Finally, the most sophisticated, but also the most informative, is the confocal arrangement of the spectrometer, where the focus, i.e. the intersection of the beams of incident and emitted radiation very narrowly collimated by the capillary optics, shifts to the depth of the measured material. This review paper summarizes the principles and possibilities of these methods, their advantages and limitations, and thus gives information for their use for specific needs. The use is illustrated by examples of specific measurements of art objects, realized in various laboratories, but especially in the laboratory of the authors of this paper.
Article
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Tools for three-dimensional elemental characterization are available on length scales ranging from individual atoms, using electrons as a probe, to micrometers with X-rays. However, for larger volumes up to millimeters or centimeters, quantitative measurements of elemental or isotope densities were hitherto only possible on the surface. Here, a novel quantitative elemental characterization method based on energy-resolved neutron imaging, utilizing the known neutron absorption cross sections with their ‘finger-print’ absorption resonance signatures, is demonstrated. Enabled by a pixilated time-of-flight neutron transmission detector installed at an intense short-pulsed spallation neutron source, for this demonstration 3.25 million state-of-the-art nuclear physics neutron transmission analyses were conducted to derive isotopic densities for five isotopes in 3D in a volume of 0.25 cm3. The tomographic reconstruction of the isotope densities provides elemental maps similar to X-ray microprobe maps for any cross section in the probed volume. The bulk isotopic density of a U-20Pu-10Zr-3Np-2Am nuclear transmutation fuel sample was measured, agrees well with mass-spectrometry and is evidence of the accuracy of the method.
Article
A confocal synchrotron radiation micro X-ray fluorescence (μ-SRXRF) imaging setup based on the Kirkpatrick–Baez (K-B) mirrors and polycapillary optics is described and characterized at the hard X-ray micro-focusing beamline (BL15U1)...
Chapter
This chapter focuses on the basic principles of X-ray fluorescence (XRF) and micro-XRF imaging applicable to cultural heritage research, presenting basic figures of merit and application examples based on the use of advanced laboratory and synchrotron radiation sources. Related methods of analysis making use of absorption edge phenomena by X-ray absorption spectroscopy, including X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy will also be discussed.
Article
Confocal X‐ray fluorescence (XRF) spectrometry can be used to perform three‐dimensional elemental analysis, which is impossible using general micro XRF spectrometry without any collimating optics in the detection channel. In this study, we designed, for the first time, a new confocal line XRF (C‐L‐XRF) system that can obtain elemental information of a larger area and higher intensity in XRF analysis than conventional confocal point XRF (C‐P‐XRF) analysis. We evaluate the basic performance of C‐L‐XRF, such as XRF intensity and horizontal and depth spatial resolutions. We identified that the spatial resolution of C‐L‐XRF in the horizontal and depth directions is approximately 2.9 and 2.6 times those of conventional C‐P‐XRF. However, it is possible to obtain an XRF intensity that is approximately 33 times higher than C‐P‐XRF intensity. C‐L‐XRF is expected to be effective for analyzing wide‐area samples such as layered samples.
Article
The fern Pteris vittata has been the subject of numerous studies because of its extreme arsenic hyperaccumulation characteristics. However, information on the arsenic chemical speciation and distribution across cell types within intact frozen-hydrated Pteris vittata fronds is necessary to better understand the arsenic biotransformation pathways in this unusual fern. While 2D X-ray absorption spectroscopy imaging studies show that different chemical forms of arsenic, As(III) and As(V), occur across the plant organs, depth-resolved information on arsenic distribution and chemical speciation in different cell types within tissues of Pteris vittata have not been reported. By using a combination of planar and confocal μ-X-ray fluorescence imaging and fluorescence computed μ-tomography, we reveal, in this study, the localization of arsenic in the endodermis and pericycle surrounding the vascular bundles in the rachis and the pinnules of the fern. Arsenic is also accumulated in the vascular bundles connecting into each sporangium, and in some mature sori. The use of 2D X-ray absorption near edge structure imaging allows for deciphering arsenic speciation across the tissues, revealing arsenate in the vascular bundles and arsenite in the endodermis and pericycle. This study demonstrates how different advanced synchrotron X-ray microscopy techniques can be complementary in revealing, at tissue and cellular levels, elemental distribution and chemical speciation in hyperaccumulator plants.
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内容提要 本书系统阐述了三维高分辨率共焦显微成像与测量技术理论, 首先总结了共焦显微技术的发展、演变历程; 接着利用标量衍射理论和傅里叶光学全面阐述了共焦显微成像的基本理论, 以空间域和频率域、相干和非相干、二维和三维成像相结合的思路进行系统论述, 并对共焦显微技术所涉及的各主要点进行分别阐述; 重点以作者及其团队在共焦显微超分辨成像与超精密测量理论和技术方面的研究为基础, 分类阐述了高分辨率共焦显微测量技术的基本原理、技术特点、系统实现和实验研究等; 最后简要介绍了共焦显微层析理论和技术延拓方面所取得的重要进展, 并对共焦显微技术本身进行了整体评价。本书可供共焦扫描光学显微技术、精密光学检测及测量技术、光学层析成像技术等领域科研工作者参考。
Book
Cambridge Core - Materials Science - X-ray Microscopy - by Chris Jacobsen
Article
X-ray diffraction measurements from minizones were tested using a confocal arrangement of polycapillary focusing optics. Diffraction was measured by scanning the angle of the polycapillary focusing optics receiving the diffracted X-rays while maintaining the confocal point with the polycapillary of the incident X-rays. When the inside of a sample consisting of two or more substances was scanned, the crystalline material could be identified from the X-ray diffraction pattern at the focal point. It was also possible to obtain the spatial distributions of crystals in a polycrystalline sample that otherwise appeared homogeneous at a macroscopic level. Particularly, differences in the packing density of crystals within a sample could be observed. Though the beam constructed via the polycapillary optics had a large angular divergence at the focal point and the angular resolution of the obtained diffraction pattern was low, the spatial distribution analysis of the crystal phases in inhomogeneous samples was possible.
Article
Details of corrosion process of the steel sheet under stress load in the solutions have not been understood well. In this case, it is important to observe the corrosion process in liquid solutions by using nondestructive analytical method. Therefore, we applied a confocal micro-XRF analytical method for this purpose. This method enables a nondestructive elemental imaging near the surface of the materials in the solution. We prepared a sample cell where a Zn plating steel sheet was placed under stress load in NaCl solution. Zn and Fe XRF images were successfully observed in situ for 5 days in two analytical modes: cross sectional XRF imaging and depth-selective XRF imaging.
Article
Confocal X-ray fluorescence analysis is a non-destructive method that enables the determination of the elements depth distribution in the examined sample. Accurate determination of the elements depth distributions in various samples from measured depth profiles is very demanding, and generally, a valid procedure has not been developed as yet. The main aim of this work was to design and test a universal simplified calculation procedure, which would allow the calculation of the approximate shape of the depth profiles for a sample formed from layers of a given thickness and composition. To confirm the proposed calculation method, the standard reference material NIST 1412 was used, which is formed by a homogeneous multicomponent glass containing oxides of several measurable elements. This research compares the results of the measured and calculated depth profiles in the glass reference material, where the resulting depth curves correspond almost perfectly.
Article
Full-text available
Current approaches for assessing a confocal micro‐X‐rayfluorescence–probing volume involve the use of sharp knife edges, thin films, or wires, which are moved through this volume. The fluorescence radiation excited in the material of the object is measured, and profiles are built to enable the determination of the full width at half maximum in any of the three axes of the excited volume. Such approaches do not provide information on the shape of the volume, and the consequent alignment of both used lenses is made based on the position of the maxima of the registered intensity measurements. The use of particles that are smaller than the interaction volume (isolated enough to prevent the influence of nearby particles) and translated through the interaction volume (3D scan) is presented as an alternative methodology to determine the confocal probing volume. Spherical shaped uranium particles with diameter of 1–3 μm originally produced for scanning electron microscopy analysis calibration purposes were used in this study. The results obtained showed that the effectively probed confocal volume has a distinct prolate spheroidal shape that is longer in the axis of the confocal detector than it is wide on the axes of the plane perpendicular to it. The diameter in the longest axis (tilted accordingly to the angle between the two silicon drift detectors) was found to be approximately 25 μm, whereas the shorter was found about 15 μm each, with a volume of about 3,000 μm3.
Chapter
This chapter introduces state-of-the-art synchrotron-based techniques in quantification, imaging, speciation of metals, and structure characterization of metal-binding biomolecules in environmental and biological samples. SRXRF has been widely applied in quantification of metals in different samples. The focused synchrotron-based X-ray can image metals down to nm resolution at two or three dimensions. XAS has been used for chemical speciation of different metals. In combination with SRXRF and XAS, it can also realize spatial and chemical imaging. The structure of metal-binding biomolecules can be characterized by PX and/or XAS. In all, quantification, imaging, speciation of metals, and the probing of the sub-molecular structure of metals in interactions with their surrounding environment through synchrotron-based techniques can help to unravel the speciation of toxic metals in linkage with their mobility in the environment and potential toxicity to organisms and humans.
Article
Full-text available
The status of microscopic X-ray fluorescence analysis with tube excitation and synchrotron radiation is reviewed in terms of the lateral resolution, minimum detection limits and elemental sensitivity that can be achieved. As illustrations, the utilization of two typical state-of-the-art instruments for the analysis of geological material is described; one of the instruments is based on tube excitation, the other is installed at a synchrotron X-ray source. The analytical implications of the use of X-ray microprobes installed at a third generation storage ring, and in particular at the European Synchrotron Radiation Facility (ESRF), are discussed.
Article
Advantages of X-ray fluorescence with the use of Synchrotron Radiation are emphasized (intensity, polarization, tunability of energy). The experimental set-up and the fast computer system for the data reduction without standards are presented. The results are in good agreement with standard references. Examples of applications are presented: old coins and potteries were studied in archaeological domain; metal alloys were analyzed; element composition of bulk samples of volcanic rocks, sublimates and aerosols were determined.
Article
The use of polycapillary lenses in x-ray microanalysis and x-ray diffractometry is considered. Lenses with focal spot diameters from 0.5–1 mm down to 5–10 µm ensure an increased flux on the sample under investigation by 2–3 orders of magnitude. The combination of a standard microfocus x-ray tube of 50–100 W power with such a lens permits fluxes to be obtained comparable to those at workstations for microanalysis attached to a synchrotron. The use of polycapillary lenses requires specialized x-ray tubes. A new type of tube for obtaining a high photon flux with low divergence has been developed. The possibility of realizing new high-efficiency portable x-ray spectrometers and diffractometers based on polycapillary optics is considered. Copyright © 2000 John Wiley & Sons, Ltd.
Article
Physikalische Methoden der Archäometrie liefern den Kunsthistorikern und Archäologen wichtige Informationen. Materialspezifische Größen geben Aufschluss über Alter, Authentizität, Herkunft und Herstellungstechniken sowie Alterserscheinungen von Gegenständen. Insbesondere die Röntgenanalyse hat in jüngster Zeit wertvolle Beiträge hierzu geliefert. Dabei spannt sich ein weiter Bogen von den Mysterien ägyptischer Augenschminke über die Herstellungstechnik römischer Gläser bis zur Authentizitätsuntersuchung mittelalterlicher Silberstiftzeichnungen.
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