Journal of Synchrotron Radiation最新文献

Gaining insight into structural and compositional transformations occurring at the electrode/electrolyte interface during the operation of electrochemical systems is fundamental to understanding and, thus, optimizing their performance. Such an analysis must be performed in operando conditions, owing to the potential, electrolyte and time dependence of these transformations. Here, the use of X-ray photoelectron spectroscopy (XPS) is particularly attractive due to its surface sensitivity and ability to provide quantitative information on the oxidation state and chemical environment of an element. In specific instrumental configurations [e.g. in `dip-and-pull' (D&P) or `meniscus' setup], it can be used to analyse not only the electrode but also the electrolyte side of the interface, under in situ/operando conditions. In this article, we discuss how D&P XPS can provide unique information on both sides of the electrode/electrolyte interface, briefly review publications demonstrating its capabilities, highlight the challenges the method faces, and share our views on its future developments. This article aims to provide a practical guide to new D&P synchrotron users and help them to understand the technique, and physical phenomena that may impede the acquisition of reliable data.

We present Gaia, a monolithic array of 96 high-purity germanium pixel detectors integrated with a custom low-noise application-specific integrated circuit (ASIC) and a field-programmable gate array (FPGA)-based data acquisition system. The sensor operates at ∼100 K using a commercial closed-cycle cryocooler, with the in-vacuum electronics thermally isolated from the cold finger to ensure thermal stability. The system demonstrates an average energy resolution of 711 eV at 122 keV, measured using a ⁵⁷Co source, and 253 eV at 5.89 keV, measured with ⁵⁵Fe across all channels. The readout architecture incorporates a high-performance FPGA paired with a dual-core ARM processor, forming a complete embedded Linux-based computing platform. Communication between the processor and FPGA is handled via memory-mapped I/O, and data are streamed over high-speed gigabit Ethernet. A full-scale 384-pixel Gaia detector, based on this 96-element module, is currently under fabrication.

In this paper we discuss adaptations to the BioLogic stopped-flow module (SFM)-400 stop-flow rapid mixing apparatus to enhance reliability for use on a small angle X-ray scattering (SAXS) beamline. Issues with the standard capillary holders are discussed and a 3D printed alternative is presented. The reliability of the new design against leakage is reported. Alternate resins with enhanced solvent tolerance are trialled and discussed.

With the start of the user program at the European XFEL in 2017, and more recently with the LCLS-II upgrade, the X-ray repetition rate at X-ray free-electron lasers (XFELs) has been pushed into the kilo- and megahertz regimes. These high X-ray repetition rates provide an increase in the integrated flux at these facilities by orders of magnitude, potentially facilitating measurements that were previously infeasible due to signal-to-noise constraints. However, the high repetition rates lead to new challenges for sample delivery and a shorter time for the sample to recover between X-ray pulses. For solution-phase techniques, the X-ray-sample interactions will strongly perturb or even vaporize the sample jet. Although the sample can be replenished, up to X-ray repetition rates of ∼100 kHz, by flowing the jet at high speeds, this does not completely mitigate the jet perturbations. In this work, we present a characterization of the jet perturbations induced by the high X-ray repetition rates at the European XFEL. We show how these can introduce background signals in time-resolved X-ray solution scattering data measured at the Femtosecond X-ray Experiments (FXE) instrument. We show that it is possible to mitigate these experimental artifacts by employing an alternating excitation scheme combined with careful background subtraction and that implementing this approach in the experimental design outperforms more simple background subtraction schemes. The methodology, the observations and analysis results are discussed in relation to the evolving landscape of XFEL sources.

The high-energy imaging beamline MOGNO was recently designed, installed and commissioned at the Sirius fourth-generation synchrotron radiation source at the LNLS in Brazil. MOGNO, a micro- and nano-imaging beamline, has as primary source a 3.2 T superbend permanent magnet dipole with a critical energy of 19.15 keV and operates in a cone-beam geometry. The present paper addresses the commissioning experiments in propagation-based phase-contrast imaging and microtomography, revealing high-precision details of a wide range of non-stained biological samples with minimal preparation. We illustrate the potential of non-destructive fast high-resolution microtomographic imaging, particularly for fine anatomical studies of Brazilian biological specimens. Three-dimensional investigations reveal the internal morphology of the head of a dengue fever vector mosquito (Aedes aegypti) and of the whole embryo of a reptile (Brasiliscincus agilis) and of an amphibian (Eleutherodactylus cochranae), as well as the features inherent in an archaeological artefact (Galeocerdo cuvier tooth) and a fish fossil bone (Elopomorpha incertae sedis).

The design, calibration and initial application of a non-contact high-temperature furnace developed for in situ synchrotron X-ray experiments are presented. The system enables a stable operation up to 1000°C, with heating rates exceeding 6000°C min^-1 and thermal stability better than ±2°C. Temperature calibration was performed using (i) direct measurements with a thermocouple to characterize heating and cooling ramp rates and map temperature gradients along the x, y and z axes; and (ii) synchrotron X-ray diffraction to track the ferrite-to-austenite (body-centered cubic to face-centered cubic) phase transition in an iron grain under beamline conditions. The furnace's contactless geometry provides full translational and rotational freedom, with 360° rotation and wide tilt capabilities, making it fully compatible with a range of diffraction and imaging techniques. Its 3D-printed modular body includes closable apertures for auxiliary functions such as active cooling or X-ray fluorescence. The design is easily customizable for diverse experimental requirements and can be adapted to most beamlines. The furnace has been implemented at the ID03 beamline of the European Synchrotron Radiation Facility (ESRF), which supports dark-field X-ray microscopy (DFXM), 3D X-ray diffraction, magnified topotomography, phase-contrast tomography and diffraction contrast tomography. As a first application, a DFXM case study on a cold-rolled Al1050 sample during isothermal annealing is presented. The imaging of a selected grain before and after the heat treatment reveals strain relaxation and grain growth. This furnace offers a robust and flexible platform for high-temperature synchrotron studies across materials science, including metals, ceramics and energy materials. It is now part of the ESRF sample environment pool and is available to all users.

Understanding the chemical processes that occur during the solvothermal synthesis of functional nanomaterials is essential for their rational design and optimization for specific applications. However, these processes remain poorly understood, primarily due to the limitations of conventional ex situ characterization techniques and the technical challenges associated with in situ studies, particularly the design and implementation of suitable reactors. Here, we present a versatile reactor suitable for in situ X-ray scattering, X-ray spectroscopy and infrared spectroscopy studies performed during solvothermal synthesis under autoclave-like, inert conditions. The reactor enables precise control of the temperature between -20°C and 200°C, pressure up to 8 bar, magnetic stirring, and injection of gas or liquids. The reactor's capabilities are demonstrated by comprehensively studying the solvothermal synthesis of magnetite nanoparticles from iron acetylacetonate in benzyl alcohol through in situ X-ray scattering and spectroscopy, and attenuated total reflection infrared (ATR-IR) spectroscopy.

It is now well established that multilayer coated gratings may offer high diffraction efficiencies over the tender X-ray range, from about 1 keV to 5 keV, covering the gap between single layer coated grating monochromators and crystal monochromators. Nevertheless, few beamlines in the world are using such gratings in their monochromator. The successful implementation of a multilayer grating monochromator requires producing a matched pair of a multilayer grating and a multilayer mirror, and this matching is not straightforward as it must account for different incidence angles and refraction effects on each element. Here we review the realization of the multilayer grating monochromator of the SIRIUS beamline which has been successfully in service for several years. We show how, by alternating computer simulation with our diffraction code and measurements, we could optimize the monochromator transmission on a very wide energy range. After the grating was coated, it was found that the angle of optimal efficiency versus photon energy was significantly different from what was predicted by a simple conformal model of binary layers. Layer interdiffusion and profile smoothing during the deposition process must be added to the multilayer model to reproduce the measured data. The critical adjustment of the mirror multilayer period is achieved by the lateral translation of the mirror, which was given a small transverse period gradient. The monochromator is thus providing high transmission efficiency in the 1 to 5 keV energy range, more than 30% over 2.5 keV and up to 46% at 4.6 keV.

The Coherent X-ray Scattering beamline at the Pohang Light Source-II was constructed in 2011 for coherent diffraction imaging and has now been upgraded in its focusing optics, diffractometer, detectors and endstation. The enhanced photon flux density and modified endstation have enabled routine Bragg coherent diffraction imaging and microbeam diffraction, while the newly implemented ptychography setup has enhanced nano-imaging capability in transmission geometry. Because coherent diffraction imaging and microbeam diffraction share the same upstream optics, switching between techniques requires only minor adjustments to slit settings, mirror pitch and the sample-to-detector distance, enabling efficient integration of user programs without compromising instrument performance. This paper details the upgrade and the new capabilities of the beamline.

In this article we present SELUN, a novel X-ray photon counting hybrid pixel detector developed at DECTRIS Ltd for coherent diffraction imaging techniques at synchrotron facilities. Its notable features are a pixel size of 100 µm × 100 µm arranged in a matrix of 192 × 192 elements, the possibility of use of both silicon and high-Z sensors to guarantee high quantum efficiency across a wide range of incoming X-ray energies, fast front-end electronics equipped with instant retrigger technology working in non-paralyzable counting mode, and high frame rates capability up to 120 kfps thanks to two on-chip data-compression mechanisms. Optimized towards speed to cope with the enhanced brilliance of fourth-generation synchrotron sources, it shows remarkable count rate saturation values ranging from about 30 to 60 Mcts s^-1 pixel^-1, depending on the sensor material and value of the incoming X-ray energy, and energy-resolution figures of 664 eV r.m.s. for a silicon sensor and 1.22 keV r.m.s. for a cadmium zinc telluride (CZT) sensor.