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Electron probe microanalysis (EPMA) is a powerful tool for chemical characterization of materials on a microscopic scale. However, EPMA has the drawback that its information volume has a spatial extent of some 100 nm to a few µm. With the introduction of new electron sources, i.e., Schottky Thermal Field and Cold Field Emitter, where the electron beam is focused down to a few nm, measurements can be nowadays performed on the sub-micrometer scale. The goal of the work is to reveal the chemical composition of structures smaller than the excitation volume. New strategies are presented where the acquisition is performed at different positions on the sample and as a scan across a fine structure by using one or more single beam energies. Besides the well-known Monte-Carlo simulation, a deterministic model is also used. The deterministic model is based on moment equations of the Boltzmann equation. Inverse modeling is presented for several case studies. Due to the highly complex nonlinearity of the inverse model, an ill-posed and well-posed problem is shown as well. Finally, the method is extended to reconstruct 2D structures, i.e., rectangular shaped particles, with heterogeneous composition on lateral and depth scale.

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Lab managers and users of scanning electron microscope or electron probe microanalyzer facilities aiming for qualitative or quantitative X-ray analyses require comprehensive, yet flexible documentation structures for their daily work and available reference material, with a complete X-ray data library, a repository of energy- and wavelength-dispersive spectra, and an instrument scheduling mechanism. An online multilaboratory database system available at https://de-ma.ch is presented with the primary goals of providing information on microanalytical reference materials, analytical setups, characteristic X-ray data, and for managing reservation and training requests. This website is designed for multiuser facilities, where experience ranges from beginners to expert users. Registered users will find these tools useful in developing and maintaining high-quality, reproducible, and efficient analyses, whereas lab managers will keep records of their microanalytical reference material database and analytical protocols. The database also serves an educational purpose by (a) providing information on reference materials, (b) encouraging students to select appropriate X-ray lines to analyze, (c) providing analytical setups for point analysis or mapping, (d) identifying unknown X-ray lines, (e) displaying energy- or wavelength-dispersive spectra, and (f) recalculating mineral formula from quantitative wt% analysis results, based on a number of oxygen atoms or cations.

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The accurate characterisation of centreline segregation requires precise measurements of composition variations over large length scales (10 - 1 $^{-1}$ m ${\rm {m}}$ ) across the centreline of the cast product, while having high resolution, sufficient to quantify the significant composition variations between dendrites due to microsegregation at very small length scales (10 - 5 m $^{-5}{\rm {m}}$ ). This study investigates the potential of a novel microscopy technique, named Synchrotron Micro X-ray Flurorescence (SMXRF), to generate large-scale high-resolution segregation maps from a steel sample taken from a thin slab caster. Two methods, Point Analysis and Regression Analysis, are proposed for SMXRF data calibration. By comparing with the traditional Laser-Induced Breakdown Spectroscopy (LIBS), and Electron Probe Micro Analyser (EPMA) techniques, we show that SMXRF is successful in quantitative characterisation of centreline segregation. Over large areas (e.g. 12 × $\times$ 16 mm 2 ${\rm {mm}}^2$ ) and at high resolution (10-50 µ m $\mu\text{m}$ pixel size) various techniques yield comparable outcomes in terms of composition maps and solute profiles. The findings also highlight the importance of both high spatial resolution and large field of view to have a quantitative, accurate, and efficient measurement tool to investigate segregation phenomena.

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The assembly of Ga alloys with Ni or Ni alloy has been widely developed for various low-temperature applications in recent years. In the constituent Ni-Ga binary system, however, the phase equilibrium with the phase "NiGa5" and its stability has scarcely been investigated. The present study used the diffusion couple technique combined with SEM-EPMA and XRD analysis to examine the phase stability and the homogeneity range of the phase. The results show that "NiGa5" is a stable phase in the binary system with little homogeneity range and suggest that the peritectic reaction L+Ni3Ga7→NiGa5 lies between 112.0 and 115.5 °C. This work provides new information for the modification of the Ga-rich low-T region of the Ni-Ga phase diagram.

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Observed photon count rates must be corrected for detector dead time effects for accurate quantification, especially at high count rates. We present the "constant k-ratio" method, a new approach for calibrating dead time for wavelength dispersive spectrometers by measuring k-ratios as a function of beam current. The method is based on the observation that for a given emission line at a specific take-off angle and electron beam energy, the intensity ratio from two materials containing the element should remain constant as a function of beam current, if the dead time calibration is accurate. The method has the advantage that it does not rely on the linearity of the beam current picoammeter, yet also allows the analyst to evaluate the picoammeter linearity, another critical parameter in EPMA calibration. By simultaneously comparing k-ratios for all spectrometers, one can also ascertain k-ratio consensus, essential for inter-laboratory comparisons. We also introduce improved dead time expressions and provide best practices on how to perform these instrument calibrations using this new "constant k-ratio" method. These improvements enable quantitative analysis of major and minor elements with high accuracy at high beam currents, simultaneously with trace elements with high sensitivity, for point analyses and X-ray mapping.

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It is often assumed that electron backscatter and continuum (bremsstrahlung) productions emitted from electron-solid interactions during X-ray microanalysis in compounds can be extrapolated from pure element observations by means of the assumption of average atomic number, or Z-bar (Z¯). For pure elements the average Z is equal to the atomic number, but this direct approach fails for compounds. The use of simple atomic fractions yields completely spurious results, and while the commonly used mass fraction Z averaging produces fairly reasonable results, we know from physical considerations that the mass of the neutron plays only a negligible role in such interactions below ∼1 MeV. Therefore, including the mass or atomic weight in such calculations can only introduce further errors in these models. We present an expression utilizing atomic fractions of the atomic numbers of the elements in the compound (Z fraction), with an exponent to account for the variation in nuclear screening as a function of the element Z value.

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An electron probe X-ray microanalyzer (EPMA) is an essential tool for studying chemical composition distribution in the microstructure. Quantifying chemical composition using standard specimens is commonly used to determine the composition of individual phases. However, the local difference in chemical composition in the standard specimens brings the deviation of the quantified composition from the actual one. This study introduces how to overcome the error of quantification in EPMA in the practical aspect. The obtained results are applied to evaluate the chemical composition of retained austenite in multi-phase steel. Film-type austenite shows higher carbon content than blocky-type one. The measured carbon contents of the retained austenite show good coherency with the calculated value from the X-ray diffraction.

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To improve the Al/Steel bimetallic interface, Eu was firstly added to the Al/Steel bimetallic interface made by liquid-solid casting. The effects of Eu addition on the microstructure, mechanical capacities, and rupture behavior of the Al/Steel bimetallic interface was studied in detail. As the addition of 0.1 wt.% Eu, the morphology of eutectic Si changed from coarse plate-like to fine fibrous and granular in Al-Si alloys, and the average thickness of the intermetallic compounds layer decreased to a minimum value of 7.96 µm. In addition, there was a more sudden drop of Fe in steel side and the Si in Al side was observed to be more than the other conditions. The addition of Eu did not change the kinds of intermetallic compounds in the Al/steel reaction layer, which was composed of Al5Fe2, τ1-(Al, Si)5Fe3, Al13Fe4, τ5-Al7Fe2Si, and τ6-Al9Fe2Si2 phases. The addition of the element Eu did not change the preferential orientation of the Al5Fe2, τ1-(Al, Si)5Fe3, Al13Fe4, τ5-Al7Fe2Si, and τ6-Al9Fe2Si2 phases, but refined the grain size of each phase and decreased the polar density of Al5Fe2 phase. Eu was mainly enriched in the front of the ternary compound layer (τ6-Al9Fe2Si2) near the Al side and steel matrix. The Fe and Al element distribution area tended to narrow in the interface after the addition of 0.1 wt.% Eu, which is probably because that Eu inhibits the spread of Al atoms along the c-axis direction of the Al5Fe2 phase and the growth of Al13Fe4, τ5-Al7Fe2Si, and τ6-Al9Fe2Si2 phases. When the Eu content was 0.1 wt.%, the shear strength of the Al/Steel bimetal achieved a maximum of 31.21 MPa, which was 47% higher than the bimetal without Eu.

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Genetic differentiation in aquatic organisms is usually shaped by drainage connectivity. Sympatric aquatic species are thus expected to show similar population differentiation patterns and similar genetic responses to their habitats. Water bodies on the Qinghai-Tibet Plateau (QTP) have recently experienced dramatic physicochemical changes, threatening the biodiversity of aquatic organisms on the "roof of the world." To uncover ecological genetics in Tibetan loaches (Triplophysa)-the largest component of the QTP ichthyofauna-we characterized population differentiation patterns and adaptive mechanisms to salinity change in two sympatric and phylogenetically closely related Tibetan loaches, T. stewarti and T. stenura, by integrating population genomic, transcriptomic, and electron probe microanalysis approaches. Based on millions of genome-wide SNPs, the two Tibetan loach species show contrasting population differentiation patterns, with highly geographically structured and clear genetic differentiation among T. stewarti populations, whereas there is no such observation in T. stenura, which is also supported by otolith microchemistry mapping. While limited genetic signals of parallel adaption to salinity changes between the two species are found from either genetic or gene expression variation perspective, a catalog of genes involved in ion transport, energy metabolism, structural reorganization, immune response, detoxification, and signal transduction is identified to be related to adaptation to salinity change in Triplophysa loaches. Together, our findings broaden our understanding of the population characteristics and adaptive mechanisms in sympatric Tibetan loach species and would contribute to biodiversity conservation and management of aquatic organisms on the QTP.

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One of the most common scientific methods to study the chemical composition of bone matter is energy-dispersive X-ray spectroscopy (EDS). However, interpretation of the data obtained can be quite complicated and require a thorough understanding of bone structure. This is especially important when evaluating subtle changes of chemical composition, including the age-related ones. The aim of current study is to create a method of processing the obtained data that can be utilized in clinical medicine and use it to evaluate the age evolution of bone chemical composition. To achieve this goal, an elemental composition of 62 samples of cadaver compact bone, taken from the skull base (age: Me = 57.5; 21/91(min/max); Q1 = 39.5, Q3 = 73.75), was studied with EDS. We used the original method to estimate the amount of Mg2+ cations. We detected and confirmed an increase of Mg2+ cation formula amount in the bone apatite, which characterizes age-related resorption rate. Analysis of cation estimated ratio in a normative bone hydroxylapatite showed an increase of Mg2+ amount (R = 0.43, p = 0.0005). Also, Ca weight fraction was shown to decrease with age (R = - 0.43, p = 0.0005), which in turn confirmed the age-dependent bone decalcification. In addition, electron probe microanalysis (EPMA) and X-ray diffraction analysis (XRD) were performed. EDS data confirmed the EPMA results (R = 0.76, p = 0.001). In conclusion, the proposed method can be used in forensic medicine and provide additional data to the known trends of decalcification and change of density and crystallinity of mineral bone matter.

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Comprehensive mineralogical and petrographic studies require analytical methods capable to report the distribution of major to trace elements within crystals in order to unravel their formation conditions and subsequent evolution. Additionally, the investigation of transition elements (e.g., Ti, V, Cr, Mn, Fe, and Zn) is essential for the comprehension of substitution processes within colored minerals. This study is conducted on a zoned kyanite crystal from a deformed quartz vein found within garnet-kyanite-biotite-hematite-plagioclase±staurolite±sillimanite paragneiss of Thassos Island, Greece. Herein, we show the efficiency of combining conventional, for example, cathodoluminescence, electron probe microanalysis (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and new methods, for example, micro-laser-induced breakdown spectroscopy (µLIBS), micro-X-ray fluorescence (µXRF), and Raman spectroscopy, to determine the chemical and crystallographic features of minerals. The simple chemistry of this crystal offers an ideal case to compare and valuate the potential of combined spectroscopy techniques to analyze minerals. We demonstrate that µLIBS and µXRF are perfectly adapted to perform multi-element imaging of major to trace elements down to the ppm level within a pluricentimetric crystal (2.3 x 0.5 cm) prior to quantitative analyses. We also highlight the benefit of cathodoluminescence and Raman mapping in the investigation of crystallographic features within minerals. The multispectroscopic approach enabled us to correlate growth stages of kyanite with the polymetamorphic history of the sample. Our results also highlight the spatial dependence of Ti for the generation of blue zonation by Fe2+-Ti4+ substitutions with Al3+.

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The present study was undertaken to examine the effect of iron, manganese, copper and magnesium on the microstructural characteristics of Al-11%Si-2%Cu-Mg-based alloy referred to as 396 under different working conditions. The results show that strontium (Sr) has high affinity to react with magnesium (Mg), resulting in reduced effectiveness as eutectic silicon modifier or age hardening agent. In addition, Sr alters the sequence of the precipitation of the α-AlFeMnSi phase from post-eutectic to pro-eutectic which would harden the soft α-Aluminum matrix. The mechanism is still under investigation. The interactions between iron (Fe) and Mg and Sr-Mg result in the formation of serval dissolvable intermetallics during the solutionizing treatment such as ß-AlFeSi, π-AlFeMgSi and Q-AlMgSiCu phases. The study also emphasizes the role of modification and grain refining as well as intermetallics in porosity formation and hardness of samples aged in the temperature range 155-240 °C.

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OBJECTIVE: To determine the effect of patient age (young or mature), anatomical location (shallow/deep and central/peripheral) and microscopic site (intertubular/peritubular) on dentine mineral density, distribution and composition. METHODS: Extracted posterior teeth from young (aged 19-20 years, N = 4) and mature (aged 54-77 years, N = 4) subjects were prepared to shallow and deep slices. The dentine surface elemental composition was investigated in a SEM using Backscattered Electron (BSE) micrographs, Energy Dispersive X-ray Spectroscopy, and Integrated Mineral Analysis. Qualitative comparisons and quantitative measures using machine learning were used to analyse the BSE images. Quantitative outcomes were compared using quantile or linear regression models with bootstrapping to account for the multiple measures per sample. Subsequently, a Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM) was used to mill large area (100 µm) cross-sections to investigate morphology through the dentine tubules using high resolution secondary electron micrographs. RESULTS: With age, dentine mineral composition remains stable, but density changes with anatomical location and microscopic site. Microscopically, accessory tubules spread into intertubular dentine (ITD) from the main tubule lumens. Within the lumens, mineral deposits form calcospherites in the young that eventually coalesce in mature tubules and branches. The mineral occlusion in mature dentine increases overall ITD density to reflect peritubular dentine (PTD) infiltrate. The ITD observed in micrographs remained consistent for age and observation plane to suggest tubule deposition affects overall dentine density. Mineral density depends on the relative distribution of PTD to ITD that varies with anatomical location. SIGNIFICANCE: Adhesive materials may interact differently within a tooth as well as in different age groups.

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Cd1-xZnxTe (0 ≤ x ≤ 0.1) ingots were obtained by Bridgman's method using two different speeds in order to find the optimal conditions for single-crystalline growth. Crystalline quality was studied by chemical etching, the elemental composition by wavelength dispersive spectroscopy (WDS), tellurium (Te) precipitates/inclusions concentration by differential scanning calorimetry (DSC), optical transmission by Fourier transformed infrared spectrometry (FTIR), and band gap energy (Egap) by photoluminescence (PL). It was observed that the ingots grown at a lower speed were those of the best crystalline quality, having at most three grains of different crystallographic orientation. The average dislocations density in all of them were similar and correspond to materials of good quality. EPMA results indicated that the homogeneity in the composition was excellent in the ingots central part. The concentration of Te precipitates/inclusions in all ingots was below the instrument (DSC) detection limit, 0.25% wt/wt. In the case of wafers from Cd0.96Zn0.04Te and Cd0.90Zn0.10Te ingots, the optical transmission was better than that of commercial materials and varied between 60% and 70%, while for pure CdTe, the transmission range was between 50% and 55%, the latter being decreased by the presence of Te precipitates/inclusions. The band gap energy Eg of different wafers was experimentally obtained by PL measurements at 76 K. We observed that Eg increased with the Zn concentration of the wafers, following a linear regression comparable to those proposed in the literature, and consistent with the results obtained with other techniques.

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Electron-probe microanalysis of uranium and uranium alloys poses several problems, such as rapid oxidation, large poorly constrained correction factors, and a large number of characteristic x-ray lines. We show that U-metal can grow 10 nm of oxide within ~20 s of air exposure, increasing to 15­20 nm within a few minutes, which can produce a 30% quantification error at 5 kV. A 15 nm carbon coating on the UO2 reference material also produces an ~30% quantification error of the uncoated but surface oxidized U sample at 5 kV. Correcting for both the coating and oxide improved the analysis accuracy to better than ±1% down to 7 kV and ~2% at 5 kV, but the error increases strongly below this. The measurement of C in U identified a previously unreported U N6­O4 line interference on the C Kα peak, which can produce over 1% error in the analysis total. Oxide stoichiometry was demonstrated to have only a small impact on quantification. The measurement of the O Kα and U Mα mass absorption coefficients in U as 9,528 and 798 cm2/g, respectively, shows good agreement with recently published values and also produces small differences in a quantification error.

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Since the 1960s, thicknesses and compositions of thin-film specimens have been determined by using the nondestructive technique of electron probe microanalysis. This approach, refined in the 1990s, is based upon models of the ionization depth distribution, the so-called ϕ(ρz) distribution, and is capable of analyzing layered specimens. Most of these quantification models have led to commercial programs. However, these programs may have possible limitations: some may not be directly compatible with modern computers, they often are "black boxes" making it difficult to assess the reliability of the results, and they are sometimes expensive enough to restrain many labs from purchasing them. We present a user-friendly, free, open-source program, BadgerFilm, implementing a documented ϕ(ρz) model and algorithms allowing the quantification of stratified samples. The program has the ability to calculate absolute X-ray intensities that can be directly compared with Monte Carlo simulations. We give a detailed explanation for the operation of the employed ϕ(ρz) model in thin films. A wide range of detailed Monte Carlo simulations and experimental data have been used to evaluate and validate the accuracy of the implemented algorithms. BadgerFilm demonstrated excellent quantification results for the films and in many cases for the substrates.

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This, the second in a series of articles present a new framework for considering the computation of uncertainty in electron excited X-ray microanalysis measurements, will discuss matrix correction. The framework presented in the first article will be applied to the matrix correction model called "Pouchou and Pichoir's Simplified Model" or simply "XPP." This uncertainty calculation will consider the influence of beam energy, take-off angle, mass absorption coefficient, surface roughness, and other parameters. Since uncertainty calculations and measurement optimization are so intimately related, it also provides a starting point for optimizing accuracy through choice of measurement design.

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Electron probe microanalysis is a nondestructive technique widely used to determine the elemental composition of bulk samples. This was extended to layered specimens, with the development of appropriate software. The traditional quantification method requires the use of matrix correction procedures based upon models of the ionization depth distribution, the so-called ϕ(ρz) distribution. Most of these models have led to commercial quantification programs but only few of them allow the quantification of layered specimens. Therefore, we developed BadgerFilm, a free open-source thin film program available to the general public. This program implements a documented ϕ(ρz) model as well as algorithms to calculate fluorescence in bulk and thin film samples. Part 1 of the present work aims at describing the operation of the implemented ϕ(ρz) distribution model and validating its implementation against experimental measurements and Monte Carlo simulations on bulk samples. The program has the ability to predict absolute X-ray intensities that can be directly compared to Monte Carlo simulations. We demonstrate that the implemented model works very well for bulk materials. And as will be shown in Part 2, BadgerFilm predictions for thin film specimens are also shown to be in good agreements with experimental and Monte Carlo results.

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Dosimetry is a technique that quantitatively measures the ionizing radiation absorbed by matter. The present study was conducted on the barites from a mine at Dongargaon in Central India. Morphological and structural analysis of proposed sample was carried out using X-ray diffraction and standard error of the mean. Thermal analysis and chemical composition of the proposed sample were carried out using thermogravimetric analysis and differential thermal analysis, and electron probe microanalysis. Thermoluminescence (TL) studies on a natural barite sample were performed using a Nucleonix TL1009I TL reader following sample irradiation with γ-rays generated from a 60 Co irradiation source. A broad TL glow curve was observed after TL study that was then deconvoluted using TLanal deconvolution software. Trapping parameters from the sample such as activation energy (E), order of kinetics (b), and frequency factor (s) were calculated using Chen's peak shape method, the initial rise method, and Ilich's method. The results indicated that the natural barite sample could be used in high-dose TL dosimetric applications in various fields.

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Al-Cu-Li alloys are famous for their high strength, ductility and weight-saving properties, and have for many years been the aerospace alloy of choice. Depending on the alloy composition, this multi-phase system may give rise to several phases, including the major strengthening T1 (Al2CuLi) phase. Microstructure investigations have extensively been reported for conventionally processed alloys with little focus on their Additive Manufacturing (AM) characterised microstructures. In this work, the Laser Powder Bed Fusion (LPBF) built microstructures of an AA2099 Al-Cu-Li alloy are characterised in the as-built (no preheating) and preheat-treated (320 °C, 500 °C) conditions using various analytical techniques, including Synchrotron High-Energy X-ray Diffraction (S-HEXRD). The observed dislocations in the AM as-built condition with no detected T1 precipitates confirm the conventional view of the difficulty of T1 to nucleate on dislocations without appropriate heat treatments. Two main phases, T1 (Al2CuLi) and TB (Al7.5Cu4Li), were detected using S-HEXRD at both preheat-treated temperatures. Higher volume fraction of T1 measured in the 500 °C (75.2 HV0.1) sample resulted in a higher microhardness compared to the 320 °C (58.7 HV0.1) sample. Higher TB volume fraction measured in the 320 °C sample had a minimal strength effect.