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A new parallel-beam wavelength dispersive (PB-WDS) X-ray emission spectrometer was constructed at the external proton beamline at the Microanalytical Centre of the Joˇzef Stefan Institute in Ljubljana. The spectrometer combines polycapillary X-ray optics for efficient X-ray collection with diffraction on a flat crystal analyzer and achieves energy resolution in the eV range. The whole set-up is enclosed within a He bag to be able to operate in the tender X-ray energy range. The basic design is described together with the results of characterization measurements yielding the main operation characteristics. Finally, an application for the micro-PIXE analysis of biological tissue is demonstrated exploiting both spatial and energy resolution of the new set-up.

The valence-to-core (VtC) K x-ray emission spectroscopy (XES) in the tender x-ray range is emerging as a powerful analytical technique used to study the electronic structure of third-row elements within complex bulk materials. With dedicated tender x-ray emission spectrometer coupled with laboratory excitation source, such analysis can be successfully performed also in a smaller lab. In this work, we have gathered VtC x-ray emission spectra of several sulfur and chlorine compounds measured previously in our home lab using Johansson type tender x-ray emission spectrometer and MeV proton excitation. Measured spectra are compared to the results of one-electron density functional theory (DFT) calculations. Theoretical spectra were found in good agreement with the experimental data with few exceptions where systematic discrepancies were observed. The latter was attributed to the simultaneous K and M shell ionization induced by MeV protons, which is not included in the oneelectron DFT theoretical framework. In order to confirm this also experimentally, VtC x-ray emission spectra of few selected S and Cl compounds induced with three different proton energies were recorded yielding characteristic KM ionization satellite lines, confirmed by their emission energies as well as the dependence of their relative intensity on proton energy.

Kα x-ray emission induced by 2 MeV protons in thick Ti metal, TiO, Ti2O3, TiO2, MgTiO3, FeTiO3, TiC, TiN, TiB2, Cr metal, Cr2O3, CrO2, CrO3, K2Cr2O7 targets was measured using a wavelength dispersive spectrometer employing Johansson geometry to study chemical sensitivity of X-ray spectra. In the spectra the main Kα1 and Kα2 components as well as the KαL1 multiple ionization satellites were clearly resolved. The Kα1 and Kα2 peak positions and widths were extracted directly from the measured spectra in a consistent way. The results were compared with the existing data obtained by proton and photon induced ionization mechanisms, with the results of multiplet calculations, and with the observed chemical effects found in the related experimental Kβ spectra measured on the same Ti and Cr compounds at earlier times. The results obtained confirm linear correlations of the Kα1 first moments (M1) and the Kα center of gravity energy shifts with the central metal formal oxidation state, as well as between the Kα1 line widths and the Kα1 - Kβ1 M1 and/or centre of gravity energy shifts. The Kα energy shifts calculated by multiplet structure method for Cr compounds agreed with the experimentally obtained trends. Keywords: X-ray emission spectroscopy, High resolution X-ray spectra, Ti and Cr compounds, PIXE, Multiple ionization satellites.

The journal of physical chemistry / C 126(12), 5435 - 5442 (2022). doi:10.1021/acs.jpcc.1c10622, X-ray Raman spectroscopy (XRS) is an emerging spectroscopic technique that utilizes inelastic scattering of hard X-rays to study X-ray absorption edges of low Z elements in bulk material. It was used to identify and quantify the amount of carbonyl bonds in a cathode sample, in order to track the redox reaction inside metal–organic batteries during the charge/discharge cycle. XRS was used to record the oxygen K-edge absorption spectra of organic polymer cathodes from different multivalent metal–organic batteries. The amount of carbonyl bond in each sample was determined by modeling the oxygen K-edge XRS spectra with the linear combination of two reference compounds that mimicked the fully charged and the fully discharged phases of the battery. To interpret experimental XRS spectra, theoretical calculations of oxygen K-edge absorption spectra based on density functional theory were performed. Overall, a good agreement between the amount of carbonyl bond present during different stages of battery cycle, calculated from linear combination of standards, and the amount obtained from electrochemical characterization based on measured capacity was achieved. The electrochemical mechanism in all studied batteries was confirmed to be a reduction of double carbonyl bond and the intermediate anion was identified with the help of theoretical calculations. X-ray Raman spectroscopy of the oxygen K-edge was shown to be a viable characterization technique for accurate tracking of the redox reaction inside metal–organic batteries., Published by Soc., Washington, DC

The existing external beamline at the Microanalytical Center of the Jo��ef Stefan Institute (JSI) in Ljubljana has been currently upgraded in order to extend the capabilities towards in-air PIXE imaging across relatively large sample surface area (~ 1 cm2) with lateral resolution of sub 100 ��m. For that purpose, a doublet of magnetic quadrupole lenses was installed on the beamline together with the newly designed exit nozzle with a 200 nm Si3N4 exit window resulting finally in ~ 50��50 mm2 lateral resolution. Additionally, an in-vacuum beam chopper was installed before the exit nozzle to measure the proton dose deposited on the sample. The beam characterization results are presented together with the first application from the field of biology, namely quantitative concentration maps of a longitudinal section of a whole thick wheat grain.

In this work, valence-to-core (VtC) Kβsulfur X-ray emission spectroscopy (XES) was used to perform quantitative analysis of different sulfur compounds produced in a lithium sulfur (Li–S) battery during discharge. The analysis is based on the theoretical sulfur KβXES spectra obtained from ab initio quantum chemical calculations based on density functional theory. The emphasis is given to the Kβsulfur XES spectra of the polysulfide molecules (Li2Sx, x = 2,…,8) produced electrochemically within the Li–S battery. Ab initio molecular dynamics calculations are used further to calculate also the Kβspectra of Li2Sx dissolved in a model solvent. Calculated spectra were directly compared with the experimental ones collected with a Johansson type tender XES spectrometer on laboratory synthesized Li2Sx reference standards and pre-cycled battery cathodes. These results demonstrate that sulfur VtC XES can be used effectively to quantitatively analyze electrochemical sulfur conversion, also in a smaller laboratory without the need for large scale synchrotron facilities.

In order to evaluate the efficacy of ammonia photocatalysis, it is necessary to continuously monitor its concentration during the process. This paper presents ammonia concentration monitoring using a low cost (non-professional) electronic device. The device is based on an open source electronic platform, and it is composed of the MQ-137 ammonia detection sensor, connected to the Croduino Basic 2 board. Sensitive material of the sensor is a metal oxide (SnO2). The change in the ammonia concentration causes a change in the electrical resistance, which is measured and used for the ammonia concentration estimation. Four measurements, with ammonia concentration ranging from 0-500 ppm were performed in the controlled environment. With the purpose of the device calibration and repeatability test, along with a low-cost device, the monitoring was carried out also with a professional device, Geotech GA5000 gas analyser. Using the information provided in the sensor datasheet, together with the measured data, the measurement error of the low-cost device was assessed. After calibration, ammonia concentrations measured using a low-cost device, are consistent with those obtained from the professional device.

Wavelength-dispersive X-ray spectrometry is used to examine the influence of multiple ionization satellites induced by 3–5 MeV energy helium ion beams upon the accuracy of particle-induced X-ray emission analysis (PIXE). The work extends our prior study of elements magnesium, aluminum and silicon and their oxides to elements phosphorus, chlorine, potassium, calcium, titanium and chromium and, for the latter two, their oxides. Fitting of the spectra with Voigtian peaks enables construction of a database that comprises the mean energies and the relative intensities of up to four distinct satellite groupings. This database provides an empirical means for inclusion of one peak per satellite group when modelling energy-dispersive spectra. This is a useful step towards improving the accuracy of PIXE analysis of materials using helium beams ; an example of this is provided using a spectrum recorded by the Curiosity rover on Mars.

International audience; In a lithium/sulfur (Li/S) battery, the reduction of sulfur along discharge involves a particular mechanism, where the active material successively dissolves into the electrolyte to form lithium polysulfides intermediate species (Li2Sx), with x being a function of state of charge. In this work, sulfur K-edge Resonant Inelastic X-ray Scattering measurements were applied for the characterization of different Li2Sx polysulfide standard solutions. High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy allowed to separate clearly the pre-edge absorption peak corresponding to terminal sulfur atoms from the main absorption peak due to internal atoms, and to evaluate quantitatively the evolution of the peak area ratio as a function of the polysulfide chain length. Results of this experimental work demonstrate that the normalized area of the pre-edge is a reliable fingerprint of Li2Sx mean chain length in agreement with recent theoretical predictions. As a perspective, this work confirms that operando HERFD XAS can be used to differentiate polysulfides mean composition, which is key issue in the characterization of Li/S cells.

The Curiosity rover’s alpha particle X-ray spectrometer employs simultaneous XRF and PIXE to analyze rock and soil samples on the Martian surface. The PIXE is accomplished by alpha particle emission from 244Cm, and the XRF by the L X-rays from the daughter. Recent work [1] has shown that fits to these spectra, which extend over a 23 keV range, are improved by accounting rigorously for both X-ray detector non-linearity and the alpha-induced multiple ionization satellites. This work necessitated the insertion of an interim satellite database into the GUPIX-based fitting code GUAPX. The database was assembled from a rather sparse literature and involved considerable extrapolation and interpolation. For 3- 5 MeV alphas, the summed intensity in the KL1 , KL2 , KL3 satellites is of similar order to that of the KL0 diagram line. It is clear that the accuracy of laboratory-based PIXE with alpha particles can be improved by including these in the spectrum fitting procedure. We have therefore started an effort to refine and extend the interim satellite database, using WDX spectroscopy at IJS and IRB. Work has been completed on magnesium, aluminum, silicon and their oxides. The spectra below are from Si and SiO2 ; all individual Voigtians are shown. Comparison of our results for individual line energies and intensities with those of the database has enabled small corrections to the latter. The work will now proceed to elements of higher atomic number. [1] J. L. Campbell, B. Ganly, C. M. Heirwegh, J. A. Maxwell, Nucl. Instr. Meth. B414, 2018, 38.

High energy resolution X-ray emission spectroscopy employing wavelength dispersive (WDS) crystal spectrometers can provide energy resolution on the level of core-hole lifetime broadening of the characteristic emission lines. While crystal spectrometers have been traditionally used in combination with electron excitation for major and minor element analysis, they have been rarely considered in proton induced X-ray emission (PIXE) trace element analysis mainly due to low detection efficiency. Compared to the simplest flat crystal WDS spectrometer the efficiency can be improved by employing cylindrically or even spherically curved crystals in combination with position sensitive X-ray detectors. When such spectrometer is coupled to MeV proton excitation, chemical bonding effects are revealed in the high energy resolution spectra yielding opportunity to extend the analytical capabilities of PIXE technique also towards chemical state analysis. In this contribution we will focus on the high energy resolution PIXE (HR-PIXE) spectroscopy in the tender X-ray range performed in our laboratory with our home-built tender X-ray emission spectrometer. Some general properties of high energy resolution PIXE spectroscopy in the tender X-ray range are presented followed by an example of sulfur speciation in biological tissue illustrating the capabilities as well as limitations of HR-PIXE method used for chemical speciation in the tender X-ray range.

A new parallel beam wavelength dispersive X-ray emission spectrometer for high energy resolution PIXE analysis using focused proton microbeam has been constructed and installed at the microprobe of the J. Stefan Institute. Polycapillary X-ray optics is used to enhance the solid angle of X-ray collection and to transform collected proton-induced X-rays into quasi parallel beam which is analyzed using diffraction on a flat crystal. The spectrometer is installed in a vacuum chamber and operates in the 2–10 keV energy range. The main characteristics and operational properties are presented together with the results of first characterization measurements. Finally, two selected experimental examples are given illustrating the capabilities of the spectrometer in PIXE analysis and fundamental research in atomic physics.

For a successful experiment, it is of utmost importance to provide a consistent detector description. This is also the main motivation behind DD4hep, which addresses detector description in a broad sense including thegeometry and the materials used in the device, and additional parameters describing, e.g., the detection techniques, constants required for alignment and calibration, description of the readout structures and conditions data. An integral part of DD4hep is DDG4 which is a powerful tool that converts arbitrary DD4hep detector geometries to Geant4 and provides access to all Geant4 action stages. It is equipped with a comprehensive plugins suite that includes handling of different IO formats; Monte Carlo truth linking and a large set of segmentation and sensitive detector classes, allowing the simulation of a wide variety of detector technologies. In the following, recent developments in DD4hep/DDG4like the addition of a ROOT based persistency mechanism for the detector description and the development of framework support for DDG4 are highlighted. Through this mechanism an experiment’s data processing framework can interface its essential tools to all DDG4 actions. This allows for simple integration of DD4hep into existing experiment frameworks. For a successful experiment, it is of utmost importance to provide a consistent detector description. This is also the main motivation behind DD4hep, which addresses detector description in a broad sense including the geometry and the materials used in the device, and additional parameters describing, e.g., the detection techniques, constants required for alignment and calibration, description of the readout structures and conditions data. An integral part of DD4hep is DDG4 which is a powerful tool that converts arbitrary DD4hep detector geometries to Geant4 and gives also access to all Geant4 action stages. It is equipped with a comprehensive plugins suite that includes handling of different IO formats; Monte Carlo truth linking and a large set of segmentation and sensitive detector classes, allowing the simulation of a wide variety of detector technologies. In the following, we will showcase recent developments in DD4hep/DDG4 like the addition of a ROOT based persistency mechanism for the detector description and the development of framework support for DDG4. Through this mechanism an experiment’s data processing framework can exhibit its essential tools to all DDG4 actions. This allows for the easy integration of DD4hep in existing experiment frameworks.

In order to evaluate the efficacy of ammonia photocatalysis, it is necessary to continuously monitor its concentration during the process. This paper presents ammonia concentration monitoring using a low cost (non-professional) electronic device. The device is based on an open source electronic platform, and it is composed of the MQ-137 ammonia detection sensor, connected to the Croduino Basic 2 board. Sensitive material of the sensor is a metal oxide (SnO2). The change in the ammonia concentration causes a change in the electrical resistance, which is measured and used for the ammonia concentration estimation. Four measurements, with ammonia concentration ranging from 0-500 ppm were performed in the controlled environment. With the purpose of the device calibration and repeatability test, along with a low-cost device, the monitoring was carried out also with a professional device, Geotech GA5000 gas analyser. Using the information provided in the sensor datasheet, together with the measured data, the measurement error of the low-cost device was assessed. After calibration, ammonia concentrations measured using a low-cost device, are consistent with those obtained from the professional device.

These proceedings cover recent measurements of rare charmless decays B + → K ‾ ⁎ ( 892 ) 0 K ⁎ ( 892 ) + , B 0 → η ′ K ⁎ ( 892 ) 0 and B 0 → π 0 π 0 with a data sample of 772 × 10 6 B B ‾ pairs collected at the ϒ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. In the decay channel B + → K ‾ ⁎ ( 892 ) 0 K ⁎ ( 892 ) + an excess of 2.73σ is observed, which corresponds to B = ( 0.77 − 0.30 + 0.35 ± 0.12 ) × 10 − 6 and a longitudinal polarization f L = 1.06 ± 0.30 ± 0.14 . A signal strength of 5.0σ is measured in the decay channel B 0 → η ′ K ⁎ ( 892 ) 0 with the corresponding B = ( 2.6 ± 0.7 ± 0.2 ) × 10 − 6 and a CP asymmetry of A C P = − 0.22 ± 0.29 ± 0.07 . Finally we report an updated measurement of B 0 → π 0 π 0 decays, with a measured branching fraction of B = ( 0.90 ± 0.12 ± 0.10 ) × 10 − 6 .

The electronic structure of phosphorus, sulfur, and chlorine in compounds with T_d and C_3v local symmetries was studied with high-resolution Kβ X-ray emission spectroscopy (XES) in the tender X-ray range. Measured spectra are compared to the results of ab initio quantum chemical calculations based on density functional theory (DFT). The spectral structure is reproduced by the model spectra of isolated XO^{; ; ; ; 4n–}; ; ; ; and XO^{; ; ; ; 3n–}; ; ; ; (X = P, S, or Cl) anions incorporating only the first coordination sphere around the central atom. The main spectral components can be explained by the molecular orbital theory. Finally, the potential of XES spectroscopy combined with DFT calculations to study the electronic structure of third-row elements in a slightly larger molecule is investigated.

An experimental and theoretical study of phosphorus electronic structure based on high energy resolution X-ray emission spectroscopy was performed. The Kα and Kβ emission spectra of several phosphorus compounds were recorded using monochromatic synchrotron radiation and megaelectronvolt (MeV) proton beam for target excitation. Measured spectra are compared to the results of ab initio quantum chemical calculations based on density functional theory (DFT). Clear correlation between energy position of the Kα emission line and the phosphorus formal oxidation state as well as DFT-calculated number of valence electrons is obtained ; measured energy shifts are reproduced by the calculations. Chemical sensitivity is increased further by looking at the Kβ emission spectra probing directly the structure of occupied molecular orbitals. Energies and relative intensities of main components are given together with the calculated average atomic character of the corresponding molecular orbitals involved in transitions.

We present results of recent development of the color X-ray camera, type SLcam®, allowing detection of X-ray images with few microns resolution. Such spectral resolution is achieved with the use of high-quality polycapillary optics combined with sub-pixel resolution. Imaging of Siemens star resolution test chart reveals that the resolution limit of SLcam® can go down to nearly 5μm. Several real sample examples of measurements carried out at the laboratory, synchrotron, and particle-induced X-ray emission beamlines are shown. This is the first time SLcam® is used as particle-induced X-ray emission detector. Copyright © 2015 John Wiley & Sons, Ltd.

Kα X-ray emission spectra from a series of phosphorus, sulfur, and chlorine containing compounds covering the full range of oxidation states were measured employing high energy resolution proton induced X-ray emission (PIXE) spectroscopy in the tender X-ray range. Measurements were accompanied by quantum chemistry calculations based on density functional theory (DFT). Clear energy shifts of the Kα lines were measured in correlation with the formal oxidation state for all three elements. This correlation was improved even further using the effective charge based on the DFT calculated valence electron population. Finally, it is demonstrated that the oxidation state analysis based on the Kα energy shifts can be used also for a quantitative analysis of the proportion of separate low-Z species in mixed valence systems.

Application of new analytical tools providing insight into the mechanism of lithium– polysulfide formation in the cathode and their interaction with the host matrix and electrolyte is essential for further development of Li–S batteries. In this work, resonant inelastic X-ray scattering (RIXS) measurements at the sulfur K-edge were performed on the Li–S battery in operando mode to study the lithium-polysulfide formation during the discharge process. The relative amounts of each sulfur compound in the cathode during the discharge process were determined from the linear combination fit using reference spectra measured on standard sulfur compounds. Because of resonant excitation condition the sensitivity for the lithium–polysulfide detection was significantly enhanced, while the sulfate signal from the electrolyte was heavily suppressed. In addition, the influence of self- absorption effects in the analysis was minimized due to fixed excitation energy. Consequently, a full quantitative analysis could be performed for the conventional Li–S battery consisting of sulfur–carbon composite cathode free from any additives and a LiTFSI based electrolyte.

In this paper we report an X-ray emission study of bulk aqueous sulfuric acid. Throughout the range of molarities from 1 M to 18 M the sulfur Kβ emission spectra from H2SO4 (aq) depend on the molar fractions and related deprotonation of H2SO4. We compare the experimental results with results from emission spectrum calculations based on atomic structures of single molecules and structures from ab initio molecular dynamics simulations. We show that the S Kβ emission spectrum is a sensitive probe of the protonation state of the acid molecules. Using non-negative matrix factorization we are able to extract the fractions of different protonation states in the spectra and the results are in good agreement with the simulation for the higher part of the concentration range.

International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the carbon disulphide CS 2 molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO) absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppression of the LUMO contribution with respect to the emission signal from the higher unoccupied molecular orbitals, which results in the modulation of the total RIXS profile. At even larger negative photon-energy detuning from the resonance, the excitation-energy dependence of the RIXS profile is dominated by the onset of electron dynamics triggered by a coherent excitation of multiple electronic states. Furthermore, our study demonstrates that in the hard x-ray regime, localization of the S 1s core hole occurs in CS 2 during the RIXS process because of the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Core-hole localization leads to violation of the symmetry selection rules for the electron transitions observed in the spectra.

We describe the way we designed and built embedded labs while teaching students the basic principles of digital electronics. By this means, we also introduced students to the world of embedded microcontrollers with the thought that they might someday build their own circuits.

The color X-ray camera SLcam® is a full-field, single photon detector providing scanning-free, energy and spatially resolved X-ray imaging. Spatial resolution is achieved with the use of polycapillary optics guiding X-ray photons from small regions on a sample to distinct energy dispersive pixels on a charged-coupled device detector. Applying sub-pixel resolution, signals from individual capillary channels can be distinguished. Therefore, the SLcam® spatial resolution, which is normally limited to the pixel size of the charge-coupled device, can be improved to the size of individual polycapillary channels. In this work a new approach to a sub-pixel resolution algorithm comprising photon events also from the pixel centers is proposed. The details of the employed numerical method and several sub-pixel resolution examples are presented and discussed.

Application of laboratory-based X-ray analytical techniques that are capable of a reliable characterization of the chemical state of sulfur within bulk battery cathode in parallel with electrochemical characterization is essential for further development of lithium-sulfur batteries. In this work, MeV proton-induced X-ray emission (XES) sulfur measurements were performed in ex situ mode on laboratory-synthesized sulfur standards and precycled battery cathodes. The average sulfur charge was determined from the energy shift of the Kα emission line and from the spectral shape of the Kβ emission spectrum. Finally, operando Kα XES measurements were performed to monitor reduction of sulfur within battery cathode during discharge. The experimental approach presented here provides an important step toward more routine laboratory analysis of sulfur-based battery systems and also other sulfur-neighboring low-Z bulk materials with emission energies in the tender X-ray range.

The existing external beamline at the Microanalytical Center of the Jožef Stefan Institute (JSI) in Ljubljana has been currently upgraded in order to extend the capabilities towards in-air PIXE imaging across relatively large sample surface area (~ 1 cm2) with lateral resolution of sub 100 µm. For that purpose, a doublet of magnetic quadrupole lenses was installed on the beamline together with the newly designed exit nozzle with a 200 nm Si3N4 exit window resulting finally in ~ 50×50 mm2 lateral resolution. Additionally, an in-vacuum beam chopper was installed before the exit nozzle to measure the proton dose deposited on the sample. The beam characterization results are presented together with the first application from the field of biology, namely quantitative concentration maps of a longitudinal section of a whole thick wheat grain.