Journal of Synchrotron Radiation最新文献

This article reports an operando X-ray absorption spectroscopy (XAS) cell and its set-up for the photocatalytic reduction of CO₂ in the gas phase. Details about the cell and set-up development and configuration are provided. The operando cell and set-up are validated from a photocatalytic point of view: the performances of two photocatalysts are successfully benchmarked with those obtained on an already existing gas phase photoreactor unit. The cell is also validated from an XAS point of view as measured Mo K-edge spectra of the photocatalyst loaded in the cell are similar to those measured for ex situ samples, prepared in a capillary. Finally, a detailed example of an operando photocatalytic experiment shows the potentiality of the developed cell to monitor photocatalysts under working conditions for gas phase CO₂ photoreduction, making the link between a shift in the absorption edge due to Mo species evolution and the deactivation of the photocatalyst. Additionally, the developed operando cell, available at Synchrotron SOLEIL on the ROCK beamline, is versatile and may actually be used for any photocatalytic gas phase reaction.

X-ray free electron lasers (XFELs) serve as advanced light sources and have become essential for investigating ultrafast dynamic phenomena in physics and materials with extraordinary resolution. Owing to the XFEL's ultrafast characteristics and short wavelengths, an arrival-timing tool is crucial for pump-probe experiments. To address this, we have developed a timing diagnostic tool employing both spectral-encoding and spatial-imaging methods at the SBP beamline for the newly constructed Shanghai Soft X-ray Free Electron Laser Facility (SXFEL). This timing tool was experimentally validated, proving that the spectral-encoding technique could achieve single-pulse measurement with an accuracy of under 40 fs [root mean square (RMS)], and exhibited a timing-jitter measurement of 90.3 fs (RMS) at the CSI endstation of SXFEL. Furthermore, the spatial-imaging approach used both polished- and rough-surface GaAs crystals, which simplifies implementation in X-ray pump-probe experiments, and allows for the characterization of X-ray pulse arrival times at the endstation without rotating the sample stage. These findings confirm that the timing diagnostic tool provides dependable high-precision temporal characterization of X-ray pulses at SXFEL, facilitating high-accuracy X-ray pump-probe experiments.

The novel design and evaluation on the NSLS-II beamline of the 3FI application-specific integrated circuit (ASIC) bump-bonded to a simple, planar, 2D segmented silicon sensor are presented. The ASIC was developed for full-field fluorescence spectral X-ray imaging (3FI). It is a small-scale prototype that features a square array of 32 × 32 pixels, and the size of the pixels is 100 µm × 100 µm. The ASIC was implemented in a 65 nm CMOS integrated circuit fabrication process. Each pixel incorporates a charge-sensitive amplifier, a shaping filter, a discriminator, a peak detector and a sample-and-hold circuit, allowing detection of events and storage of signal amplitudes. The system operates in a frameless event-driven readout mode, outputting analog values for threshold-triggered events, allowing high-speed multi-element X-ray fluorescence data acquisition. The 3FI ASIC achieves per-channel spectrometric performance at a power consumption of only 200 µW per pixel, with nearly all dissipation confined to the analog front-end. An energy resolution is measured at the level of 308 eV full width at half-maximum (FWHM) at 8.04 keV (Cu Kα), and 138 eV FWHM at 3.69 keV (Ca Kα). This per-pixel capability makes the prototype suitable for in situ trace element microanalysis in biological and environmental studies. Moreover, the frameless architecture of the detector is designed to address limitations of conventional X-ray fluorescence microscopy, which typically requires mechanical scanning, by enabling continuous high-throughput data acquisition in future full-field implementations.

Corrigendum to the article by Feuer-Forson et al. [(2024). J. Synchrotron Rad. 31, 698-705].

X-ray scanning diffraction can be used to raster-scan tissues to elucidate structural organization and other physical properties. A comprehensive data analysis package targeted to take raster X-ray diffraction (XRD) scans is vital in integrating data at multiple length and resolution scales. MuscleX-DI is an open-source software suite designed for the analysis and visualization of scanning XRD data. Developed in Python and compatible with multiple operating systems, MuscleX-DI provides an end-to-end pipeline for processing diffraction patterns and generating 2D visualizations of calculated measurements. The software supports both a graphical user interface and a command-line interface, offering tools for calibration, masking, azimuthal and radial integration, and heatmap generation. By streamlining the analysis of large XRD datasets, MuscleX-DI facilitates the extraction of structural information from heterogeneous samples, enabling new insights into tissue architecture and biomolecular organization. The scanning diffraction methodology can be applied to study complex tissues and assemblies at various length scales. Example applications include characterizing myelin organization in brain tissue and observing improved drug availability in tumors when used with ECM-degrading enzymes.

A liquid-nitrogen-cooled silicon channel-cut monochromator was developed and experimentally evaluated under high-thermal-load conditions. Under the maximum load of 417 W, the first reflecting surface exhibited a concave deformation, resulting in only an 11% reduction in vertical beam size at 16 m downstream. The deformation radius was estimated at 510 m. Despite the deformation, no significant changes were observed in the angular profile or intensity of the monochromatic beam. Interference fringes caused by edge diffraction at an upstream slit confirmed excellent preservation of spatial coherence. For the stability test of the monochromator, intensity fluctuation of the monochromatic beam was monitored and linearly fitted with upstream beam-position monitor signals, which were synchronously acquired. A high correlation (R² = 0.95) confirmed that the inherent stability of the channel-cut design remained under cryogenic cooling. Additionally, a double channel-cut monochromator configuration for fixed-exit beam operation was tested and produced the expected output beam intensity. These results confirm the feasibility of using channel-cut monochromators as high-stability high-heat-load-tolerant optical elements for next-generation synchrotron beamlines.

The Single-Particle, Clusters and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) scientific instrument at the European X-Ray Free-Electron Laser (EuXFEL) became operational with user experiments in September 2017. The unique properties and capabilities of the EuXFEL, enabling megahertz data collection rates, provide more rapid data collection with improved statistics compared with other XFEL facilities. This improves the feasibility of obtaining multiple data points in time-resolved experiments and hence enables the observation of reactions in greater detail (molecular movies). In collaboration with the SFX User Consortium (SFX UC), the SPB/SFX instrument was designed to further increase user access and research outcomes. Focusing the pulses downstream of the first interaction region [described previously (Mancuso et al., 2019)], a second experiment plane is enabled, which allows for greater optimization and more efficient usage of available beam time. Additionally, the SFX UC provided further instrumentation to provide improved capabilities on SPB/SFX. The aim for additional and extended functionality for the second interaction region was to enable sample-efficient data collection at atmospheric pressure in an environment where the sample temperature and humidity can be controlled. This paper describes the extended capabilities of the downstream interaction region of the SPB/SFX instrument and its major components, in particular its X-ray focusing optics, vacuum to atmospheric pressure out-coupling, available sample delivery methods and 2D detector, and the supporting optical laser systems for pump-probe experiments.

Refractive X-ray lenses are frequently used components at modern X-ray free-electron laser facilities. This work investigates the temporal effects of refractive optics on ultra-short X-ray pulses, particularly focusing on pulse elongation. We present a model using full Fresnel theory to study the beam profile at the focus in space and time. Refractive X-ray lenses not only change the temporal structure of the pulse, the focus size is also dependent on the incoming pulse duration. Further, we present a simplified ray-tracing model to estimate the pulse stretching effect of compound refractive lenses (CRLs), which we find to be dependent only on the dispersion and the absorption of the CRL material.

A high-speed synchrotron radiography system has been developed to facilitate in situ imaging of dynamic processes in electron beam powder bed fusion (PBF-EB). Using the P61A White Beam Engineering Materials Science beamline at PETRA III, this system achieves high temporal resolution and a spatial resolution of approximately 10 µm. The scintillator screens are coupled to a diamond plate and housed within a specialized nitrogen gas cooling system, effectively mitigating thermal stress caused by the intense synchrotron beam. These innovative components ensure stable imaging performance and enhance the system's ability to operate under extreme conditions. By resolving fringes at short propagation distances for the partially coherent beam, the imaging system has enabled the efficient visualization of crack formation and pore evolution in high-Z materials, such as nickel-based superalloys, during the PBF-EB process. These advances not only optimize imaging in extreme environments but also open new avenues for high-energy synchrotron applications, including dynamic phase imaging and laser welding studies of dense samples.

FaXToR is the first hard X-ray imaging beamline built and commissioned at the Spanish synchrotron light source ALBA, and therefore the start of user operation marks the introduction of a new imaging user community to the facility. FaXToR has pushed the implementation of a multi-scale, multimodal approach to investigate the morpho-structural changes of a number of materials within a range of applications, including biomedicine, material science, cultural heritage and paleontology. In this work, we describe the FaXToR beamline optical layout and the beam properties and we provide details on the flexible in-house design of the endstation. Beamline commissioning results are presented as well. Finally, an overview of its main applications is provided, defining the main strategic program the beamline will develop during its lifetime.