Journal of Synchrotron Radiation最新文献

A versatile scheme has been meticulously engineered for a resonant inelastic X-ray scattering spectrometer, enabling free switching between high throughput configurations with narrow spatial-resolution and low throughput setups boasting broad spatial-resolution capabilities. The high throughput mode enhances signal intensity threefold compared with setups with only the dispersive subassembly, while achieving 2.7 µm resolution within a 16 µm range. Alternatively, the broad spatial-resolution mode achieves 2.7 µm resolution across the entire optical footprint. Furthermore, the incorporation of specialized mirrors not only facilitates focusing but also paves the way for potential enhancements to the strip-shaped detector, thereby augmenting its resolution. By employing a vertically compact beam spot in conjunction with the Hettrick-Underwood optical configuration, this spectrometer attains a resolving power surpassing 12000 for 284-780 eV. This work provides an exhaustive exploration of the multifaceted attributes to the spectrometer's optical design, highlighting its adaptability and high performance in diverse experimental scenarios.

The design, development and performance of an X-ray beamline for utilizing intense, high-energy undulator radiation are presented. A double multilayer monochromator, consisting of 150 pairs of 3.33 nm periodic Cr/C multilayers, provides intense X-rays by extracting a 1% energy bandwidth from high-order harmonic undulator radiation. We experimentally confirmed a high flux of 3.4 × 10¹³ (1.3 × 10¹¹) photons s^-1 with a beam size of 0.7 (0.3) mm (vertical) × 2.9 (∼4) mm (horizontal) at an X-ray energy of 100 (267) keV with a 1.0% (1.2%) energy bandwidth. Excellent performance of the high-energy high-flux X-ray beam was proven by conducting high-speed imaging analysis.

Grating monochromators are crucial optical elements in soft X-ray free-electron laser (XFEL) beamlines. Accurately evaluating the properties of grating monochromators with near-realistic XFEL pulse is of paramount importance. In this study, we utilize the start-to-end pulse propagation method to conduct a characterization of grating monochromator performance at the FEL-1 beamline of S³FEL. The primary focuses include evaluating the monochromator's resolving power, assessing the impact of longitudinal source jitter on resolving power, analyzing diffraction effects due to grating's limited aperture and investigating the influence of thermal deformation. The novelty of this research lies in the direct use of FEL pulse propagation, providing simulation results that are more reliable than those obtained using Gaussian sources. The simulations reveal that the resolving power of the monochromator is significantly influenced by the aforementioned factors, highlighting the importance of considering real FEL beam characteristics in the design and evaluation of grating monochromators for FEL applications.

We present a dedicated and comprehensive database for experimental X-ray absorption spectroscopy (XAS) data, an integrated and user-friendly platform that combines spectrum visualization, raw data processing, spectrum matching and downloading, thereby offering a holistic solution for understanding XAS data. Leveraging the unique nature of XAS data, we have designed the MySQL table structure and developed professional plotting tools to present the data. Furthermore, the database - named XASDB - incorporates a variety of data processing tools, including data normalization as well as flexible searching and downloading options. A toolkit called XASMatch is integrated in the platform, enabling users to identify the most similar spectra within the database to their input spectra and rank with scores. An API interface is also provided to facilitate sharing data with other XAS databases and users. A total of 152 spectra measured at Beijing Synchrotron Radiation Facility for metals, oxides and minerals standards are included in the database. Applications integrated with artificial intelligence are advancing, since more high solution spectra with new standards will be available after operation of a high energy photon source to be commissioned at the end of the year.

The development of advanced catalysts for various electrochemical reactions necessitates precise characterization of their structure and dynamic evolution. This study introduces an innovative electrochemical cell tailored for operando X-ray characterizations, including X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). The cell features an adjustable aqueous electrolyte window to reduce X-ray signal absorption and an integrated flow system for efficient removal of gas products. This design enables simultaneous XRD and XAFS measurements in both fluorescence and transmission modes. Using LiCoO₂ as a model oxygen evolution reaction catalyst, operando measurements reveal structural transformations during the reaction. This device will aid in the exploration of catalyst mechanisms and the development of high-performance catalysts.

The fastest pixel array X-ray detectors can record images with nanosecond resolution. This is accomplished by storing only a few images in in-pixel memory cells. In this study, we demonstrate nanosecond resolution over a large number of images by operating a prototype detector in an event driven mode. The performance of this mode is tested by measuring the Brownian dynamics of colloidal nanoparticles. We can achieve sub-100 ns time resolution and overcome the pixel dead time by applying a cross-correlation analysis of the neighboring pixels. The approach used in this work can be extended to study time-resolved fast processes with diffraction, scattering or imaging techniques.

Deep understanding of the structural composition and growth of biological specimens is becoming increasingly important for the development of bio-based and sustainable material systems. Full-field nano-computed tomography is particularly suitable for this purpose as it allows for non-destructive 3D imaging at high spatial resolution. However, most biological samples are functionalized by water and respond sensitively to any changes in climate conditions, specifically relative humidity, by adjusting their material moisture content. To date, only a limited number of tomography instruments offer an in situ climate control option to users. These, however, are limited either by the range of relative humidity states, the long times required to change the climate state, or obstruction or attenuation of the beam. Here, the first fully automatized climate cell for in situ full-field nanotomography is presented. It has been designed, built and integrated at the nanotomography station at the P05 imaging beamline, operated by Hereon at the DESY storage ring PETRA III, Germany. The highly flexible and windowless design allows the humidity dependent swelling and shrinking of lignified plant cell walls to be studied in situ, using phase contrast nanotomography. The concept of this climate chamber can easily be integrated into other setups. It operates in the relative humidity range of 0-90% and can be controlled in a temperature range of 10-50°C. Climate conditions can be adjusted at any time, remotely from the control hutch by using a humidity generator. Results show that the developed setup maintains a stable climate during the entire duration of a tomographic scan at different humidities and does not obstruct the sample or hinder the imaging conditions. During the tomographic investigation the sample remains stable in the flow of the air stream and shows typical cell wall swelling and shrinking behaviour depending on the equilibrium moisture content. This new climate cell is now available to all users of the P05 nanotomography instrument for conditioning samples, serving a wide range of scientific applications.

Serial femtosecond X-ray crystallography (SFX) captures the structure and dynamics of biological macromolecules at high spatial and temporal resolutions. The ultrashort pulse produced by an X-ray free-electron laser (XFEL) `outruns' much of the radiation damage that impairs conventional crystallography. However, the rapid onset of `electronic damage' due to ionization limits this benefit. Here, we distinguish the influence of different atomic species on the ionization of protein crystals by employing a plasma code that tracks the unbound electrons as a continuous energy distribution. The simulations show that trace quantities of heavy atoms (Z > 10) contribute a substantial proportion of global radiation damage by rapidly seeding electron ionization cascades. In a typical protein crystal, sulfur atoms and solvated salts induce a substantial fraction of light-atom ionization. In further modeling of various targets, global ionization peaks at photon energies roughly 2 keV above inner-shell absorption edges, where sub-2 keV photoelectrons ejected from these shells initiate ionization cascades that are briefer than the XFEL pulse. These results indicate that relatively small quantities of heavy elements can substantially affect global radiation damage in XFEL experiments.

X-ray tomography is a well established technique for investigating three-dimensional bulk structures across scales, from macroscopic samples down to their microscopic constituents. The addition of a temporal dimension through dynamic, time-resolved acquisition results in four-dimensional datasets whose complexity often exceeds the processing capabilities of existing image analysis tools. To address the urgent need for a dedicated four-dimensional image analysis platform for cellular materials, we present FoamQuant-a free and open-source software package designed for batch processing and quantitative analysis of large time series of evolving cellular or foam-like materials. FoamQuant enables the extraction of key parameters such as liquid fraction (porosity), individual bubble (pore) volume and offers advanced characterization of mechanical properties, including elastic strain and stress fields as well as individual cell rearrangements. Its user-friendly, modular architecture is demonstrated through two case studies: (i) the orientation of plastic events in a flowing liquid foam, and (ii) bubble tracking in a coarsening albumin foam.

This review highlights the development and evolution of three macromolecular crystallography (MX) beamlines at the Swiss Light Source (SLS) over the past two decades. We discuss key advancements in X-ray optics, detectors, goniometers, sample changers and MX methodology, emphasizing their impact on high-throughput and high-resolution structural biology. Our contributions are presented within the broader context of global efforts in synchrotron-based MX. Looking ahead, we explore the future experiments enabled by SLS 2.0 and new opportunities at SwissFEL to enhance experimental capabilities and drive scientific discoveries.