Journal of Synchrotron Radiation最新文献

A grazing-incidence Rowland spectrometer with a collimating element for resonant inelastic soft X-ray scattering at the Veritas beamline at MAX IV, Lund, Sweden, is presented. The instrument is designed to operate in the 250-950 eV range, providing >30000 resolving power in first order. The inherent temporal resolution of the delay-line detector enables time-resolved experiments on the 270 ps time-scale and also allows for so-called time-gating which significantly improves the signal-to-noise ratio. The instrument is able to rotate around the sample position in the horizontal plane, which enables measurements of the momentum transfer in the X-ray scattering event. The instrument is prepared for installation of a polarimeter to provide full characterization of energy, momentum and polarization of the scattered photons. The design is evaluated using spectral measurements, ray-tracing, vibration and motion measurements.

We have developed a new process for the production of ultra-precise variable line spacing (VLS) lamellar diffraction gratings through nanofabrication. The process enables the fabrication of full-size X-ray gratings with sub-nanometre accuracy in groove depth, an optimal land-to-groove ratio, and uniform groove depth across the entire grating area. We also established a method for evaluating VLS groove density variation using stitched Fizeau interferometry. The measurements confirmed the exceptionally high accuracy of the VLS groove density in the fabricated gratings, which is well within the specification tolerances while the residual groove density errors are vanishingly small. The gold-coated grating demonstrated near-theoretical diffraction efficiency across the energy range of 100-1200 eV.

Compared with conventional laboratory-scale X-ray techniques, synchrotron based X-rays with higher brilliance and higher coherence allow for the investigation of various material properties with high spatial resolution. The microscopic behaviours of materials can be examined using the Hard X-ray Nanoprobe beamline (I14) at Diamond Light Source, which provides a 50 nm focused beam and has been successfully employed to identify nanoscale optoelectronic features in energy-harvesting materials such as halide perovskites that exhibit local heterogeneity. We have developed X-ray beam-induced current (XBIC) measurement capability at I14 to address the growing demand for operando analysis in energy-harvesting research. Here, we demonstrate that X-ray fluorescence (XRF)/XBIC multimodal measurements are feasible at I14 and apply these newly implemented techniques to study perovskite solar cells with various additive concentrations to understand the effect of the additive on nanoscale optoelectronic performance. This expanded operando characterization capability offers the possibility of monitoring nanometre-scale compositional variations and corresponding optoelectronic features of actual solar cell configurations.

Characterization of the stray radiation field present in the undulator systems at the European XFEL GmbH (EuXFEL) is of great importance, as the potential damage to undulator permanent magnets, electronics and diagnostic equipment depends both on the type of particles and the energy. This work presents the energy profile of the stray radiation measured in the upstream and downstream part of the undulator system near the beam pipe. The influence of machine operation settings on the radiation field intensity was also investigated. A comparison between gamma-ray energy measurements (30 keV to 1.5 MeV) and Geant4 Monte Carlo simulations shows that stray radiation in the upstream part of the undulator system originates from high-energy electrons intersecting the beam pipe wall. The intensity of the measured signal is approximately linear to the charge passing through the undulator system and to the electron energy but is inversely proportional to the square root of the undulator gap. Measurements in the upstream part of the undulator system show that the stray radiation level can be mitigated with careful choice of accelerator settings. The intensity of the radiation with energies below approximately 400 keV is higher in the downstream part of the undulator system compared with the upstream part, during regular operation. A CZT spectrometer and RADFET measurements confirm that the radiation field in the downstream part of the undulator system is dominated by low-energy synchrotron radiation (below 200 keV), which constitutes approximately 99% of the stray radiation field.

In pump-probe experiments on solid materials performed within ultrafast X-ray science, the energy deposited by an X-ray pump pulse in the sample has a non-uniform spatial distribution. The following X-ray probe pulse then measures a volume-integrated average of contributions from the differently irradiated regions of the sample. Here we propose a scheme to calculate an effective fluence of the pump pulse such that the observable of interest calculated with the effective fluence is very close to the volume-integrated observable. This approach simplifies computational simulations of X-ray irradiated solids, which typically use periodic boundary conditions and assume a uniformly irradiated simulation box. Obtaining a prediction on a volume-integrated observable requires a significant computational effort, as it is necessary to run multiple simulations for the different exposure conditions and then perform their volume integration. The proposed scheme reduces this effort to a single calculation with the effective fluence.

The energy-switchable storage ring (ESSR) is proposed as a light source that achieves high-brilliance synchrotron radiation across a wide wavelength range, from vacuum ultraviolet to hard X-rays, and efficient power consumption. The ESSR facilitates the effective operation of large-scale systems required for large experimental apparatus and stringent safety management. It also significantly improves research quality by enabling a more precise understanding of sample states, particularly subtle differences in experimental conditions that are difficult to reproduce fully.

We demonstrate a setup, combining fast scanning calorimetry with X-ray total scattering at a synchrotron beamline, allowing for in situ characterizations of the nano-scale structure of samples during and after temperature scans. The setup features a portable vacuum chamber providing a high signal-to-background ratio even on amorphous samples, which enables the observation of detailed structural changes between different sample states. We present three use cases, including one that leverages the high cooling rate of 10⁴ K s^-1 achievable by this setup. Our demonstration opens the door to various applications in materials science where understanding the interplay between structure and thermodynamics is crucial.

X-ray imaging is a fast, precise and non-invasive method of imaging which, when combined with computed tomography, provides detailed 3D rendering of samples. Incorporating propagation-based phase contrast can vastly improve data quality for weakly attenuating samples via phase retrieval, allowing radiation exposure to be reduced. However, applying phase retrieval to multi-material samples commonly requires the choice of which material boundary to tune the reconstruction. Selecting the boundary with strongest phase contrast increases noise suppression, but at the detriment of over-blurring other interfaces and potentially removing quantitative sample information. Additionally, conventional phase retrieval algorithms cannot be used for regions bounded by more than one material, requiring alternative methods. Here we present a computationally efficient, non-iterative nor AI-mediated method for applying strong phase retrieval, whilst preserving sharp boundaries for all materials within the sample. 3D phase retrieval is combined with morphological operations to prevent over-blurring artefacts from being introduced, while avoiding the potentially long convergence times required by iterative approaches. This technique, entitled 3DMPR, was tested on phase contrast images of a rabbit kitten brain encased by the surrounding dense skull. Using 24 keV synchrotron radiation with a 5 m propagation distance, 3DMPR provided a 6.8-fold improvement in the signal-to-noise ratio (SNR) of brain tissue over the standard phase retrieval procedure, without over-smoothing the images. Simultaneous quantification of edge resolution and SNR gain was performed with an aluminium-water phantom imaged using a microfocus X-ray tube at 35 kV_p and 0.576 m effective propagation distance. There, 3DMPR provided a four-fold SNR boost whilst preserving the boundary spatial resolution at 54 ± 1 µm, compared with 108 ± 2 µm using conventional phase retrieval. These results illustrate the ability of 3DMPR to create new avenues of dose reduction in clinical settings.

ALS-ENABLE is an integrated NIH P30 resource at the Advanced Light Source synchrotron at Lawrence Berkeley National Laboratory in Berkeley, California, USA. The resource provides a single portal to the combined mature structural biology technologies of macromolecular crystallography, small-angle X-ray scattering and X-ray footprinting mass spectrometry, and includes beamlines 2.0.1, 3.3.1, 4.2.2, 5.0.1, 5.0.2, 5.0.3, 8.2.1, 8.2.2, 8.3.1 and 12.3.1. This paper describes the organizational structure and the technologies of ALS-ENABLE. A case study showcasing the main technologies of the resource applied to the characterization of the SpyCatcher-SpyTag protein system is presented.

A study on the thermal load of cryogenically cooled silicon in synchrotron double-crystal monochromators is presented, based on experimental data from four different beamlines at Diamond Light Source. Different amounts of power are deposited on the first monochromator crystal by varying the storage ring current. The resulting crystal deformation causes a decline in the diffraction efficiency when power and power density are above threshold values. The results are compatible with an analytical model of thermo-mechanical deformation. Acceptable monochromator heat load values are determined with this model, to ensure optimal function of the monochromator. This model, previously tested against finite element analyses, is now validated against measured data and it will be used as a tool for initial analysis of monochromator performance on upgraded photon sources.