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Hybrid photon counting detectors have significantly advanced synchrotron research. In particular, the introduction of large cadmium telluride‐based detectors in 2015 enabled a whole new range of high‐energy X‐ray measurements. This article describes the specifications of the new PILATUS4 cadmium telluride detector and presents results from prototype testing for high‐energy powder X‐ray diffraction studies conducted at two synchrotrons. The experiments concern time‐resolved in situ solid‐state reactions at MAX IV (Sweden) and fast‐scanning X‐ray diffraction computed tomography of a battery cell at the ESRF (France). The detector's high quantum efficiency up to 100 keV, combined with a maximum frame rate of 4000 Hz, enables fast data collection. This study demonstrates how these capabilities contribute to improved time and spatial resolution in high‐energy powder X‐ray diffraction studies, facilitating advancements in materials, chemical and energy research. Demonstrations are presented of a PILATUS4 CdTe hybrid photon counting detector prototype for high‐energy powder X‐ray diffraction in materials, chemical and energy research at up to 4 kHz frame rate.

The bacterium Sporosarcina pasteurii (SP) is known for its ability to cause the phenomenon of microbially induced calcium carbonate precipitation (MICP). We explored bacterial participation in the initial stages of the MICP process at the cellular length scale under two different growth environments (a) liquid culture (b) MICP in a soft agar (0.5%) column. In the liquid culture, ex-situ imaging of the cellular environment indicated that S. pasteurii was facilitating nucleation of nanoscale crystals of calcium carbonate on bacterial cell surface and its growth via ureolysis. During the same period, the meso-scale environment (bulk medium) was found to have overgrown calcium carbonate crystals. The effect of media components (urea, CaCl2), presence of live and dead in the growth medium were explored. The agar column method allows for in-situ visualization of the phenomena, and using this platform, we found conclusive evidence of the bacterial cell surface facilitating formation of nanoscale crystals in the microenvironment. Here also the bulk environment or the meso-scale environment was found to possess overgrown calcium carbonate crystals. Extensive elemental analysis using Energy dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD), confirmed that the crystals to be calcium carbonate, and two different polymorphs (calcite and vaterite) were identified. Active participation of S. pasteurii cell surface as the site of calcium carbonate precipitation has been shown using EDS elemental mapping with Scanning transmission electron microscopy (STEM) and scanning electron microscopy (SEM).

The single photon counting microstrip detector MYTHEN III was developed at the Paul Scherrer Institute to satisfy the increasing demands in detector performance of synchrotron radiation experiments, focusing on time‐resolved and on‐edge powder diffraction measurements. Similar to MYTHEN II, the detector installed on the Material Science beamline covers 120° in 2θ. It is based on the MYTHEN III.0 readout chip wire‐bonded to silicon strip sensors with a pitch of 50 µm, and it provides improved performance and features with respect to the previous version. Taking advantage of the three independent comparators of MYTHEN III, it is possible to obtain an improvement in the maximum count rate capability of the detector at 90% efficiency from 2.9 ± 0.8 Mphotons s−1 strip−1 to 11 ± 2 Mphotons s−1 strip−1 thanks to the detection of pile‐up at high photon flux. The readout chip offers additional operation modes such as pump–probe and digital on‐chip interpolation. The maximum frame rate is up to 360 kHz in 8‐bit mode with dead‐time‐free readout. The minimum detectable energy of MYTHEN III is 4.3 ± 0.3 keV with a minimum equivalent noise charge (ENC) of 121 ± 8 electrons and a threshold dispersion below 33 ± 10 eV. The energy calibration is affected by temperature by less than 0.5% °C−1. This paper presents a comprehensive overview of the MYTHEN III detector system with performance benchmarks, and highlights the improvements reached in powder diffraction experiments compared with the previous detector generation. This paper describes in detail the upgraded MYTHEN III single photon counting microstrip detector developed for powder diffraction, and its performance.

In situ synchrotron high‐energy X‐ray powder diffraction (XRD) is highly utilized by researchers to analyze the crystallographic structures of materials in functional devices (e.g. battery materials) or in complex sample environments (e.g. diamond anvil cells or syntheses reactors). An atomic structure of a material can be identified by its diffraction pattern along with a detailed analysis of the Rietveld refinement which yields rich information on the structure and the material, such as crystallite size, microstrain and defects. For in situ experiments, a series of XRD images is usually collected on the same sample under different conditions (e.g. adiabatic conditions) yielding different states of matter, or is simply collected continuously as a function of time to track the change of a sample during a chemical or physical process. In situ experiments are usually performed with area detectors and collect images composed of diffraction patterns. For an ideal powder, the diffraction pattern should be a series of concentric Debye–Scherrer rings with evenly distributed intensities in each ring. For a realistic sample, one may observe different characteristics other than the typical ring pattern, such as textures or preferred orientations and single‐crystal diffraction spots. Textures or preferred orientations usually have several parts of a ring that are more intense than the rest, whereas single‐crystal diffraction spots are localized intense spots owing to diffraction of large crystals, typically >10 µm. In this work, an investigation of machine learning methods is presented for fast and reliable identification and separation of the single‐crystal diffraction spots in XRD images. The exclusion of artifacts during an XRD image integration process allows a precise analysis of the powder diffraction rings of interest. When it is trained with small subsets of highly diverse datasets, the gradient boosting method can consistently produce high‐accuracy results. The method dramatically decreases the amount of time spent identifying and separating single‐crystal diffraction spots in comparison with the conventional method. The capability of machine learning methods for identifying and separating artifacts that appear in a typical X‐ray diffraction image is demonstrated.

One of the challenges of all synchrotron facilities is to offer the highest performance detectors for all their specific experiments, in particular for X‐ray diffraction imaging and its high throughput data collection. In that context, the DiffAbs beamline, the Detectors and the Design and Engineering groups at Synchrotron SOLEIL, in collaboration with ImXPAD and Cegitek companies, have developed an original and unique detector with a circular shape. This detector is based on the hybrid pixel photon‐counting technology and consists of the specific assembly of 20 hybrid pixel array detector (XPAD) modules. This article aims to demonstrate the main characteristics of the CirPAD (for Circular Pixel Array Detector) and its performance – i.e. excellent pixel quality, flat‐field correction, high‐count‐rate performance, etc. Additionally, the powder X‐ray diffraction pattern of an LaB6 reference sample is presented and refined. The obtained results demonstrate the high quality of the data recorded from the CirPAD, which allows the proposal of its use to all scientific communities interested in performing experiments at the DiffAbs beamline. The DiffAbs beamline, the Detectors and the Design and Engineering groups at Synchrotron SOLEIL, in collaboration with ImXPAD and Cegitek companies, have developed an original and unique detector with a circular shape. This detector is based on the hybrid pixel photon‐counting technology and consists of the specific assembly of 20 hybrid pixel array detector (XPAD) modules.

X-ray powder diffraction is a vital analytical tool that is used in pharmaceutical science. It is increasingly used to establish the crystal structure of a new pharmaceutical substance, in particular, cocrystal or its polymorphic forms. This review begins with a brief discussion of the reliability of the structural parameters retrieved from powder patterns. Recent examples of the successful determination of crystal structures of pharmaceutical cocrystals and salts from powder diffraction data are discussed. These examples show the increased capabilities of laboratory X-ray powder diffractometers and modern software in solving actual problems of pharmaceutical science.

Electronic structure calculations indicate that the Sr₂FeSbO₆ double perovskite has a flat-band set just above the Fermi level that includes contributions from ordinary subbands with weak kinetic electron hopping plus a flat subband that can be attributed to the lattice geometry and orbital interference. To place the Fermi energy in that flat band, electron-doped samples with formulas Sr2-x LaₓFeSbO₆ (0 ≤ ₓ ≤ 0.3) were synthesized, and their magnetism and ambient temperature crystal structures were determined by high-resolution synchrotron X-ray powder diffraction. All materials appear to display an antiferromagnetic-like maximum in the magnetic susceptibility, but the dominant spin coupling evolves from antiferromagnetic to ferromagnetic on electron doping. Which of the three subbands or combinations is responsible for the behavior has not been determined.

The article describes a facile method for the preparation of a conjugate composed of silver nanoparticles and graphene oxide (Ag@GO) via chemical reduction of silver precursors in the presence of graphene oxide (GO) while sonicating the solution. The Ag@GO was characterized by X-ray photoelectron spectroscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy. The nanocomposite undergoes a color change from yellow to colorless in presence of Hg(II), and this effect is based on the disappearance of the localized surface plasmon resonance absorption of the AgNPs due to the formation of silver-mercury amalgam. The presence of GO, on the other hand, prevents the agglomeration of the AgNPs and enhances the stability of the nanocomposite material in solution. Hence, the probe represents a viable optical probe for the determination of mercury(II) ions in that it can be used to visually detect Hg(II) concentrations as low as 100 μM. The instrumental LOD is 338 nM. Graphical Abstract The mercury(II) ions interact with AgNP in Ag@GO nanocomposite and result in formation of AgHg amalgam. Therefore LSPR absorbance band of AgNPs starts to vanish. This mechanism can be used for developing a sensor for mercury(II) ions detection.

Silica has many industrial (i.e., glass formers) and scientific applications. The understanding and prediction of the interesting properties of such materials are dependent on the knowledge of detailed atomic structures. In this work, amorphous silica subjected to an accelerated alkali silica reaction (ASR) was recorded at different time intervals so as to follow the evolution of the structure by means of high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and electron pair distribution function (e-PDF), combined with X-ray powder diffraction (XRPD). An increase in the size of the amorphous silica nanostructures and nanopores was observed by HRTEM, which was accompanied by the possible formation of Si–OH surface species. All of the studied samples were found to be amorphous, as observed by HRTEM, a fact that was also confirmed by XRPD and e-PDF analysis. A broad diffuse peak observed in the XRPD pattern showed a shift toward higher angles following the higher reaction times of the ASR-treated material. A comparison of the EELS spectra revealed varying spectral features in the peak edges with different reaction times due to the interaction evolution between oxygen and the silicon and OH ions. Solid-state nuclear magnetic resonance (NMR) was also used to elucidate the silica nanostructures.

The crystal structure of ribociclib hydrogen succinate (commonly referred to as ribociclib succinate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Ribociclib hydrogen succinate crystallizes in space group P-1 (#2) with a = 6.52215(4), b = 12.67120(16), c = 18.16978(33) Å, α = 74.0855(8), β = 82.0814(4), γ = 88.6943(1)°, V = 1430.112(6) Å3, and Z = 2 at 295 K. The crystal structure consists of alternating layers of cations and anions parallel to the ab-plane. The protonated N in each ribociclib cation acts as a donor in two strong N–H⋯O hydrogen bonds to two different succinate anions. Strong O–H⋯O hydrogen bonds link the hydrogen succinate anions into chains parallel to the a-axis. N–H⋯N hydrogen bonds link the cations into dimers, with a graph set R2,2(8). The result is a three-dimensional hydrogen bond network. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)