Journal of Synchrotron Radiation最新文献

Serial synchrotron crystallography (SSX) enables structure determination from microcrystals under near-physiological, room-temperature conditions but is limited in part due to the inevitable onset of radiation damage. The ability to reduce the absorbed dose while retaining, or even improving, data quality is an attractive means of mitigating this limitation. Advances in detector technology have made the use of high-energy X-rays a routine approach in MX, improving diffraction efficiency and enhancing overall data quality. Here, we systematically evaluate low-dose SSX data collected at five different X-ray energies from 12.4 to 25 keV using a CdTe Eiger2 detector while maintaining a constant dose. Higher photon energies increased the mean diffracted intensity and signal-to-noise ratio per unit dose, and facilitated higher-resolution structure determination, even with limited crystal numbers. These findings highlight the advantages of high-energy X-rays and provide practical guidance for optimizing SSX experiments in probing protein dynamics.

The advancement of renewable energy critically depends on the rational design of catalysts, which necessitates a thorough understanding of the underlying materials. At Shanghai Synchrotron Radiation Facility (SSRF), the Energy Material beamline (E-line) has been established with three independent endstations - soft X-ray, hard X-ray and a combined soft/hard station - dedicated to fundamental studies of photovoltaic and catalytic processes, energy conversion mechanisms and related phenomena. Covering a broad photon energy range from 130 eV to 10000 eV, the combined endstation is specifically designed for in situ photoemission spectroscopy, enabling layer-by-layer analysis of materials and devices. Through techniques such as wide-range hard X-ray photoemission spectroscopy (HAXPES) and X-ray absorption spectroscopy (XAS), this endstation provides comprehensive insights into the chemical and electronic properties of catalysts. This report outlines the layout of the combined soft/hard beamline and the endstation, and evaluates its performance in terms of photon flux, energy resolution and representative applications in model catalysis. In particular, the use of in situ X-ray photoemission spectroscopy/HAXPES is expected to significantly advance the fundamental understanding of functional materials, thereby accelerating the development of efficient, reliable and affordable renewable energy solutions.

Here we report on recent progress in X-ray waveguide optics for full-field coherent imaging at the Göttingen Instrument for Nano-Imaging with X-rays (GINIX), installed at the P10 coherence beamline of the PETRA III storage ring at DESY, Hamburg. We describe fabrication methods including new materials and the corresponding characterization in terms of transmission, exit intensity distribution, far-field intensity distribution and coherence properties. In addition to single channels, which are currently used for holographic imaging, we include results on tapered waveguides and off-axis waveguide interferometers. We also address optimization of waveguide optics with respect to the novel super-resolution holography method presented by Soltau et al. [Optica (2021), 8, 818-823]. Finally, we discuss the further development of high-resolution nano-holography in view of the planned storage ring upgrade to PETRA IV.

Bragg coherent diffraction imaging (BCDI) is a lens-less technique capable of imaging the strain in a particle in the size range from 20 nm up to several micrometres. This indirect measurement technique, used in X-ray synchrotrons or free-electron lasers all over the world, requires an inversion step using iterative algorithms in order to recover the real-space complex object encoding the particle shape and deformation field. However, artefacts such as scattering peaks called `aliens' from nearby particles can affect the accuracy of the final reconstruction and require meticulous and time-consuming manual masking of the raw data. This becomes problematic for BCDI reconstructions during an experiment and/or for large volumes of data. Here, we explore the potential of machine learning, and specifically clustering techniques, to speed up this procedure while keeping the maximum spatial resolution of the object reconstruction. We also provide a user-friendly Python Jupyter notebook program available on Github.

We report on the coherence evaluation of the beamline BL09W at NanoTerasu (Tohoku University, Japan) and demonstrate X-ray multi-contrast imaging using an X-ray Talbot interferometer. Fringe visibility was measured in both the horizontal and vertical directions and analyzed to estimate the effective source size of the X-ray beam. The estimated source size in the horizontal direction was consistent with the design specification, confirming the validity of the measurements. In the vertical direction, the high visibility, exceeding 70%, indicates the remarkably high spatial coherence of the source. Multi-contrast computed tomography was successfully performed, simultaneously reconstructing absorption, phase and small-angle scattering contrasts. These results establish BL09W as a versatile beamline for coherence-based X-ray imaging.

We report the simultaneous lasing of two distinct Kα emissions at photon energies of 7.48 keV (Ni Kα₁) and 8.05 keV (Cu Kα₁). This was achieved by a population inversion induced through intense X-ray free-electron laser (XFEL) irradiation of a Cu-Ni alloy foil. This demonstration of multi-color X-ray lasing using a single XFEL source is expected to contribute significantly to the future development of X-ray lasers and their applications.

The APPLE-KNOT undulator forms composite magnetic fields by superimposing an APPLE field and a KNOT field with different period lengths, in which one serves as the dominant field to approach the target photon energy and the other acts as an additional component to transversely deflect the electron beam away from the axis. Variable polarization modes can be realized with a low on-axis heat load in the APPLE-KNOT undulator. In previous studies, APPLE arrays with shorter period length have a stronger field strength than KNOT arrays with longer period length. However, a sharp reduction in flux and an obvious degeneration in polarization degree of circular polarization mode can be observed. In this paper, such a phenomenon is theoretically studied and explained in detail. A novel undulator in which the KNOT array configuration, conventionally used for the weak field, is instead utilized to generate a strong field. Different from the traditional APPLE-KNOT undulator, the KNOT and APPLE magnet blocks are correspondingly merged to form two new blocks with significantly different specifications. The simulation results indicate that both the flux and polarization degree of circular polarization mode can be effectively improved, which are highly consistent with the theoretical prediction. The merged magnet arrays keep a symmetric structure within the single undulator period that always ensure an inherently good performance on the field integral.

This work presents the design and development of a 3D printed flow cell tailored for X-ray computed microtomography of liquid-solid systems. The flow cell is manufactured using stereolithographic printing and utilizes a novel pillarless pull-through geometry. The use of the flow cell developed for K-11 DIAD (Dual Imaging and Diffraction beamline, Diamond Light Source, UK) is demonstrated with the in situ flow and selective recovery of an Sn precipitate from solution using an organic ligand. The 3D designs and components are made freely available with this publication.

A Jungfrau-1M detector has undergone testing at Diamond Light Source. The Jungfrau series of detectors from PSI use integration and adaptive gain, to offer very high frame rate and dynamic range, suitable for high-flux and time-resolved measurements. They are becoming more widely used, to take advantage of increasing light source brightness. We report on our experiences in testing the performance of a Jungfrau-1M without illumination, with a laboratory X-ray tube and on a microfocus beamline. The Jungfrau-1M was found to be able to resolve single photons in the laboratory and on the beamline. It was confirmed that range switching from high to intermediate gain is associated with a discontinuity in the detector response. Two methods of dark frame subtraction were compared for their effect on minimizing this discontinuity. The Jungfrau-1M was found to be very effective for recording macromolecular crystallography diffraction patterns, with no apparent detriment from the discontinuity. The Diamond machine will be upgraded in 2028-9 and will operate at significantly higher flux than at present, necessitating increased use of integrating detectors, such as Jungfrau, in the future.

X-ray photon correlation spectroscopy (XPCS) is a powerful technique for evaluating microscopic dynamics using coherent X-rays. Detecting fast or small-scale dynamics typically requires strong illumination and wide-angle scattering detection; however, such conditions can cause non-negligible sample damage. This study presents a non-uniform pulse-interval XPCS approach that enables quantitative dynamical analysis with substantially reduced X-ray exposure. In conventional XPCS, continuous acquisition at uniform time intervals leads to long cumulative exposure, which can introduce radiation-induced artefacts. In this study, only 11 scattering images were recorded at non-uniform intervals, providing a broad range of delay times from a single measurement and enabling dense temporal sampling without increasing the exposure dose. The resulting dataset was analyzed using both XPCS- and X-ray speckle visibility spectroscopy (XSVS)-based schemes, and the results demonstrated that these two independent analyses yield consistent relaxation behaviors. The proposed approach offers an efficient framework for probing complex or non-Brownian dynamics in radiation-sensitive materials and expands the applicability of XPCS to soft and biological systems.