Nitrogen determination by SEM‐EDS and elemental analysis

This paper describes a methodology for the analysis of nitrogen by scanning electron microscope with an energy dispersive X‐ray spectrometer (SEM‐EDS). The methodology was developed to have a rapid and accurate alternative method to the elemental analysis by combustion and thermoconductivity detection that does not imply the decomposition of the sample. Two methods by SEM‐EDS were established: a quantitative method trying to construct a calibration curve with reference materials and another using the standardless method provided with the instrument software, and the results were compared with those obtained by elemental analysis using two instruments that work at different temperature. An important matrix effect was found when trying to construct a calibration curve for SEM‐EDS for any kind of material, being corrected when using the standardless method because this method corrects the matrix effect. The quantification of nitrogen by SEM‐EDS is a good alternative to elemental analysis by combustion and thermoconductivity detection in those cases where the sample has a very high decomposition temperature. Copyright © 2013 John Wiley & Sons, Ltd.     

Study of detection limit and sensitivity of Kα and Lα spectral lines of 47Ag, 48Cd,and 50Sn elements using polychromatic wavelength dispersive X‐ray spectrometer

The purpose of this work was to evaluate the instrumental detection limit and sensitivity for determination of elemental composition of ₄₇Ag, ₄₈Cd, and ₅₀Sn elements in the standard liquid solution with highly advanced polychromatic wavelength dispersive X‐ray fluorescence (PC‐WDXRF) spectrometer equipped with ₄₅Rh X‐ray tube. To improve the sensitivity and detection limit, the bremsstrahlung coming from ₄₅Rh source were reduced by choosing suitable primary beam filters (Al and Cu). Instrumental measuring parameters as well as study of linear calibration curves of K and L shell spectral lines were evaluated to select the best conditions for ₄₇Ag, ₄₈Cd, and ₅₀Sn quantification. The detection limit of Lα spectral lines were found to be ~3 to 5 times lower than Kα spectral lines which results in high sensitivity.     

Combined X‐ray diffraction and alpha particle X‐ray spectrometer analysis of geologic materials

The shallow interrogation depth of the lightest elements (Na, Mg, Al, and Si) detected by the particle‐induced X‐ray emission branch of the Curiosity Rover's alpha particle X‐ray spectrometer suggests that the X‐rays of these elements very likely emerge from a single mineral grain. This reality violates the assumption of atomic homogeneity at the micron scale made in both existing spectrum‐reduction approaches for the alpha particle X‐ray spectrometer. Consequently, analytical results for these elements in igneous geochemical reference materials exhibit deviations from certified concentrations in a manner that can be related to the total alkali‐silica diagram. A computer code is introduced here to provide quantitative prediction of these deviations using the mineral abundances determined from X‐ray diffraction. The latter are converted to area coverage fractions to represent the sample surface, and a fundamental parameters computation predicts the elemental X‐ray yields from each mineral and sums these. In this process, the chemistry of each individual mineral has to be varied by an iterative simplex approach; X‐ray yields are computed and compared with the peak areas from the fit of the bulk sample. When the difference between mineral yields and peak areas for each element are minimized, the mineral formulae are set and elemental X‐ray yields provided. The ratio between the summed mineral X‐ray yields and the corresponding yields based on the homogeneity assumption may then be compared directly with the concentration deviations measured in our earlier work. For several rock types, good agreement is found, thereby consolidating our understanding of the effects of sample mineralogy on alpha particle X‐ray spectrometer results. Copyright © 2017 John Wiley & Sons, Ltd.     

ED‐XRF set‐up for size‐segregated aerosol samples analysis

The knowledge of size‐segregated elemental concentrations in atmospheric particulate matter (PM) gives a useful contribution to the complete chemical characterisation; this information can be obtained by sampling with multi‐stage cascade impactors. In this work, samples were collected using a low‐pressure 12‐stage Small Deposit Impactor and a 13‐stage rotating Micro Orifice Uniform Deposit Impactor^?. Both impactors collect the aerosol in an inhomogeneous geometry, which needs a special set‐up for X‐ray analysis. This work aims at setting up an energy dispersive X‐ray fluorescence (ED‐XRF) spectrometer to analyse quantitatively size‐segregated samples obtained by these impactors. The analysis of cascade impactor samples by ED‐XRF is not customary; therefore, as additional consistency test some samples were analysed also by particle‐induced X‐ray emission (PIXE), which is more frequently applied to size‐segregated samples characterised by small PM quantities. A very good agreement between ED‐XRF and PIXE results was obtained for all the detected elements in samples collected with both impactors. The good inter‐comparability proves that our methodology is reliable for analysing size‐segregated samples by ED‐XRF technique. The advantage of this approach is that ED‐XRF is cheaper, easier to use, and more widespread than PIXE, thus promoting an intensive use of multi‐stage impactors. Copyright © 2011 John Wiley & Sons, Ltd.     

Comparison of the detection limits in the analysis of some medium atomic number elements measured with a portable XRF and an external proton beam PIXE spectrometer system

A portable X‐ray fluorescence (XRF) spectrometer system was constructed using an Amptek Mini‐X X‐ray tube and an X‐123 compact spectrometer. The spectrometer is optimised for the best limits of detection. Its analytic properties are tested and compared with an analogous laboratory‐based instrument, an external beam proton‐induced X‐ray emission spectrometry (PIXE) setup. Depending on elements in question the thick target detection limits of this portable XRF device are comparable or even lower than the PIXE setup. Copyright © 2011 John Wiley & Sons, Ltd.     

Concept of a spectrometer for resonant inelastic X‐ray scattering with parallel detection in incoming and outgoing photon energies

A spectrometer for resonant inelastic X‐ray scattering (RIXS) is proposed where imaging and dispersion actions in two orthogonal planes are combined to deliver a full two‐dimensional map of RIXS intensity in one shot with parallel detection at incoming hv_in and outgoing hv_out photon energies. Preliminary ray‐tracing simulations with a typical undulator beamline demonstrate a resolving power well above 11000 with both hv_in and hv_out near 930 eV, with a vast potential for improvement. Combining this instrument – nicknamed hv² spectrometer – with an X‐ray free‐electron laser source simplifies its technical implementation and enables efficient time‐resolved RIXS experiments.     

Preparation of sulfur reference materials that reproduce atmospheric particulate matter sample characteristics for XRF calibration

Energy‐dispersive X‐ray fluorescence (XRF) is an important tool used in routine elemental analysis of atmospheric particulate matter (PM) samples collected on polytetrafluoroethylene (PTFE) membrane filters. The method requires calibration against thin‐film standards of known elemental masses commonly obtained from commercial suppliers. These standards serve as a convenient and widely accepted interlaboratory reference but can differ significantly from samples in their chemical composition, substrate, and geometry. These differences can introduce uncertainties regarding the absolute accuracy of the calibration for atmospheric samples. Continuous elemental records of the US Interagency Monitoring of Protected Visual Environments (IMPROVE) PM monitoring network extend back to 1988. Evaluation of long‐term concentration trends and comparison with other networks demand a calibration that is accurate and precise compared with the uncertainty of the XRF measurement itself. We describe a method to prepare sulfur reference materials that are optimized for calibration of XRF instruments used to analyze IMPROVE PM samples. The reference materials are prepared by using the atmospheric form of the element, by reproducing the sample geometry, and by using the same substrate as in samples. Our results show that stable, pure, anhydrous, and stoichiometric deposits are collected onto the filter substrates, and furthermore, that the reference material masses are accurate and have acceptable uncertainty in the measurement range. The XRF response of the sulfur reference materials is similar to other commercial standards and is linear in the measurement range, and the slope of the multipoint calibration curve has very low uncertainty. These reference materials are valid for the calibration of XRF systems, and they bring improved transparency and credibility to the IMPROVE calibration. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of the utility of handheld XRF in meteoritics

We tested a handheld X‐ray fluorescence instrument with adaptable matrix correction for its suitability in meteoritics. We report here the instrument setup, precision and accuracy and present examples of applications. With a measuring time of 300 s, it is possible to collect accurate data for K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba that are needed for the identification of doubtful meteorites and the nondestructive classification of chondrites and achondrites. The factory‐supplied calibration curve of the instrument was fine tuned for our purposes with the use of well‐analyzed meteorite powders, pressed pellets and meteorite hand specimens as standards. Relative errors of 10% to 20% are reached for the mentioned elements. The instrument was tested in the hot desert of Oman while searching for meteorites and also in the laboratory while doing research on meteorites. The main applications of the instrument are the identification and classification of meteorites, the quantification of terrestrial elemental contamination (Sr and Ba) and detection of Mn‐rich desert varnish. It is possible to discriminate the major meteorite groups using Fe/Mn and Ni values. Handheld X‐ray fluorescence is also useful in identifying meteorites belonging to the same fall event. Copyright © 2011 John Wiley & Sons, Ltd.     

A three‐crystal spectrometer for high‐energy resolution fluorescence‐detected X‐ray absorption spectroscopy and X‐ray emission spectroscopy at SSRF

A Johann‐type spectrometer for the study of high‐energy resolution fluorescence‐detected X‐ray absorption spectroscopy, X‐ray emission spectroscopy and resonant inelastic X‐ray scattering has been developed at BL14W1 X‐ray absorption fine structure spectroscopy beamline of Shanghai Synchrotron Radiation Facility. The spectrometer consists of three crystal analyzers mounted on a vertical motion stage. The instrument is scanned vertically and covers the Bragg angle range of 71.5–88°. The energy resolution of the spectrometer ranges from sub‐eV to a few eV. The spectrometer has a solid angle of about 1.87 × 0^?3 of 4π sr, and the overall photons acquired by the detector could be 10⁵ counts per second for the standard sample. The performances of the spectrometer are illustrated by the three experiments that are difficult to perform with the conventional absorption or emission spectroscopy. Copyright © 2016 John Wiley & Sons, Ltd.     

Investigation of heavy metal distributions along 15 m soil profiles using EDXRF,XRD, SEM‐EDX,and ICP‐MS techniques

The research of soil contamination by heavy metal is an important field due to its environmental and health implications. The goal was to study the elemental mobility as a function of depth. For this reason, the distribution of heavy metals (V, Cr, Co, Ni, Cu, Zn, As, Sn, and Pb) was investigated along soil profiles up to a depth of 15 m at 9 sampling sites in the Nilufer industrial district (Bursa, Turkey). Elemental analyses were done with the Epsilon 5 energy dispersive X‐ray fluorescence and inductively coupled plasma mass spectrometry equipment. Particle analysis was performed with a JEOL scanning electron microscope equipped with a Si(Li) X‐ray detector. The crystallographic compositions of oxide compounds in soil samples were identified by a Rigaku X‐ray diffraction instrument. Different parameters such as the soil's chemical (mineralogical structure, pH, and electrical conductivity) and physical properties (the number of blows, the stiffness index, the liquidity index, the plasticity index, and the water content) were analyzed. To assess the mobility of the heavy metals, diffusion (D) and convection coefficients (?) were calculated with the finite difference method. Convection was determined to dominate the studied region. In addition, the mobility coefficient was determined for each metal. High mobilities were determined for Zn and V, moderate mobilities for Cr, Ni, Cu, and As, and low mobilities were determined for Co and Pb. The results revealed that elements had reached depths of up to 15 m, causing irreversible soil contamination that may lead to environmental health issues.     

Confocal macro X‐ray fluorescence spectrometer on commercial 3D printer

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 © 2017 John Wiley & Sons, Ltd.     

On‐and off‐site Raman study of rock‐shelter paintings at world‐heritage site of Bhimbetka

Rock‐shelter paintings of Bhimbetka world‐heritage site near Bhopal, India have been investigated using a portable Raman spectrometer. These paintings in the rock shelters belong to periods starting from pre‐historic to the 19th century AD (Gond period). In addition, tiny fragments of pigments (100–200 µm in size) extracted from some of the artworks were also studied in laboratory using a micro‐Raman spectrometer and analyzed using energy‐dispersive X‐ray analysis for elemental composition. Based on the Raman spectra and the elemental analysis mineral‐based pigments such as calcite, gypsum, hematite, whewellite, and goethite could be identified. A comparison of the spectra recorded on‐site using a light‐weight portable spectrometer with those using laboratory equipment is also made and discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Quantitative elemental analysis of individual particles with the use of micro‐beam X‐ray fluorescence method and Monte Carlo simulation

The aim of the work was to develop a Monte Carlo (MC) method and combine it with micro‐beam X‐ray fluorescence (XRF) technique for determination of chemical composition of individual particles. A collection of glass micro‐spheres, made of NIST (National Institute of Standards and Technoly) K3089 material of known chemical composition, with diameters in the range of 25–45 µm was investigated. The micro‐spheres were measured in a scanning micro‐beam XRF spectrometer utilising X‐ray tube as a source of primary radiation. Results obtained for low Z elements showed high dependence on particle size. It was found that the root mean square of concentration uncertainty, for the all elements present in the particle, increases with growing sample size. More accurate results were obtained for high Z elements such as Fe–Pb, as compared to others. The elemental percentage uncertainty did not exceed 14% for any particular sample and 6% for the whole group of the measured micro‐spheres as an average. Results obtained by the Monte Carlo method were compared with other analytical approaches. Copyright © 2009 John Wiley & Sons, Ltd.     

A device for X‐Ray elemental mapping using annular radioisotope source

An energy‐dispersive system is described for elemental mapping by X‐ray fluorescence spectrometry. The present study describes the design of an X‐ray fluorescence spectrometer and presents its performance in elemental mapping applications. The spectrometer is based on a new ring‐shaped collimator with a pinhole in the center of it and a ring‐shaped Am‐241 isotope mounted in the collimator as a source for excitation of X‐ray fluorescence. The photons were detected by high‐resolution Si (Li) detector coupled to a multi‐channel analyser and cooled by liquid nitrogen. In this study, we used two samples; one of them was made from pure elemental powders, and the second one was a piece of a stone and three types of maps were plotted. In the maps type one, the areas of the elements were shown with a single color. These maps only show the location of the elements in the sample. In the maps type two, the area of each element was shown with different colors because of the count (intensity) related to the area. In the third type of the maps for each element, depending on the elements' position on the sample, the counts were plotted in three dimensions. The areas with higher intensity have greater height, and areas with lower intensity have lower altitude. These two last types of maps provide information about the homogeneity or heterogeneity of the elemental distribution in the samples. The spectrometer can perform non‐destructive analyses of samples and objects in the air. Copyright © 2017 John Wiley & Sons, Ltd.     

Prototype GaAs X‐ray detector and preamplifier electronics for a deep seabed mineral XRF spectrometer

Work towards developing a prototype GaAs based X‐ray fluorescence spectrometer focusing on the detector‐preamplifier system for in situ characterisation of deep seabed minerals is presented. Such an instrument could be useful for marine geology and provide insight into hydrothermal processes. It would also be beneficial for deep sea mining applications. The GaAs photodiode was electrically characterised at 4 °C (ambient seawater temperature) and 33 °C. A system energy resolution (full width at half maximum) at 5.9 keV of 580 eV at 4°C, limited by the dielectric noise, broadening to 680 eV at 33°C, was recorded. The spectral performance of the system was characterised across the energy range 4.95 keV to 21.17 keV, at 33°C, using high‐purity X‐ray fluorescence calibration samples excited by a Mo target X‐ray tube. The charge output from the system was found to be linear with incident photon energy. The energy resolution was found to broaden from 695 eV at 4.95 keV to 735 eV at 21.17 keV, attributed to the increasing Fano noise with energy. The same X‐ray tube was used to fluoresce an unprepared manganese nodule (revealing the presence of Mn, Fe, Ni, Cu, Zn, Pb, Sr, and Mo) and a black smoker hydrothermal vent sample (containing Fe, Co, Ni, Cu, Zn, Pb, and Mo). Such a spectrometer may also find use in future space missions to study the hydrothermal vents that are believed to exist in the oceans of Jupiter's moon Europa.     

A large‐solid‐angle X‐ray Raman scattering spectrometer at ID20 of the European Synchrotron Radiation Facility

An end‐station for X‐ray Raman scattering spectroscopy at beamline ID20 of the European Synchrotron Radiation Facility is described. This end‐station is dedicated to the study of shallow core electronic excitations using non‐resonant inelastic X‐ray scattering. The spectrometer has 72 spherically bent analyzer crystals arranged in six modular groups of 12 analyzer crystals each for a combined maximum flexibility and large solid angle of detection. Each of the six analyzer modules houses one pixelated area detector allowing for X‐ray Raman scattering based imaging and efficient separation of the desired signal from the sample and spurious scattering from the often used complicated sample environments. This new end‐station provides an unprecedented instrument for X‐ray Raman scattering, which is a spectroscopic tool of great interest for the study of low‐energy X‐ray absorption spectra in materials under in situ conditions, such as in operando batteries and fuel cells, in situ catalytic reactions, and extreme pressure and temperature conditions.     

Investigation of nanoscale element distributions at surfaces with grazing incidence X‐ray spectroscopy techniques – an instrumentation study

Grazing incidence X‐ray methods are well‐established in the characterization of nanostructures at interfaces and surfaces. The purpose of the experiments reviewed in this work is the comparative characterization of different instrumentation concepts for grazing incidence X‐ray fluorescence analyses. Fluorescence scans recorded with a total reflection X‐ray fluorescence spectrometer featuring a variable angle of incidence are compared with data obtained with synchrotron radiation. The conclusions to the element distribution profiles, which are drawn from fluorescence scans carried out with the respective instrument, are compared. This way, the suitability of the total reflection X‐ray fluorescence spectrometer to complement synchrotron radiation facilities and the possibility to transfer surface and interface analyses from the synchrotron to the laboratory are assessed. The structures investigated include an Au on Si surfaces in the form of layers and particles, submicrometer‐sized droplets, a liquid film, and ions implanted into a Si wafer. Copyright © 2014 John Wiley & Sons, Ltd.     

The new PIXE‐alpha spectrometer for the analysis of Roman nummi surfaces

The particle‐induced X‐ray emission (PIXE)‐alpha portable spectrometer of the Laboratori Nazionali del Sud has been upgraded to improve X‐ray energy resolution and efficiency. A value of 124 eV at Mn Κα‐line and a factor of 3 were, respectively, achieved. These enhanced capabilities allowed the thin surface examination of 5 Roman nummi, in which previous near‐surface X‐ray fluorescence measurements revealed traces of mercury. In particular, the new version of the PIXE‐alpha spectrometer has allowed the distinction of the 2.19 keV Hg M‐line from the 2.30 keV S K‐line and the 2.34 keV Pb M‐line. Subsequent elemental association has demonstrated a correlation between surface mercury and silver. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of dispersive XAFS system for analysis of time‐resolved spatial distribution of electrode reaction

Apparatus for a technique based on the dispersive optics of X‐ray absorption fine structure (XAFS) has been developed at beamline BL‐5 of the Synchrotron Radiation Center of Ritsumeikan University. The vertical axis of the cross section of the synchrotron light is used to disperse the X‐ray energy using a cylindrical polychromator and the horizontal axis is used for the spatially resolved analysis with a pixel array detector. The vertically dispersive XAFS (VDXAFS) instrument was designed to analyze the dynamic changeover of the inhomogeneous electrode reaction of secondary batteries. The line‐shaped X‐ray beam is transmitted through the electrode sample, and then the dispersed transmitted X‐rays are detected by a two‐dimensional detector. An array of XAFS spectra in the linear footprint of the transmitted X‐ray on the sample is obtained with the time resolution of the repetition frequency of the detector. Sequential measurements of the space‐resolved XAFS data are possible with the VDXAFS instrument. The time and spatial resolutions of the VDXAFS instrument depend on the flux density of the available X‐ray beam and the size of the light source, and they were estimated as 1 s and 100 µm, respectively. The electrode reaction of the LiFePO₄ lithium ion battery was analyzed during the constant current charging process and during the charging process after potential jumping.