Synchrotron radiation research is rapidly expanding with many new sources of radiation being created globally. Synchrotron radiation plays a leading role in pure science and in emerging technologies. The Journal of Synchrotron Radiation provides comprehensive coverage of the entire field of synchrotron radiation and free-electron laser research including instrumentation, theory, computing and scientific applications in areas such as biology, nanoscience and materials science. Rapid publication ensures an up-to-date information resource for scientists and engineers in the field.
Copyright (c) 2026 International Union of Crystallography
Journal of Synchrotron Radiation, Volume 33, Part 4, 2026
Improved image reconstruction in coherent diffraction imaging using self-seeded XFEL pulses
In coherent diffraction imaging (CDI), the coherence properties of photons play critical roles in obtaining structural information from specimens without using lenses. While the impact of coherence has been widely studied in CDI, it has not been systematically investigated within the specific framework of X-ray free-electron laser (XFEL)-CDI. Here, we examined the relationship between the transverse and temporal coherence of XFEL pulses and the quality of image reconstruction using XFELs. Specifically, we investigated the properties of self-amplified spontaneous emission and self-seeding beams at an X-ray energy of 5 keV by collecting diffraction patterns from a single gold nanoparticle. Furthermore, the quality of the reconstructed images obtained using the two beam modes was compared. Our results demonstrate that the self-seeding beam offers more reliable image reconstruction that is attributable to the narrower bandwidth of the incident X-rays. This study highlights the advantages of utilizing a self-seeding beam in CDI experiments, particularly for enhancing the reliability and quality of image reconstruction.
This study demonstrates that the superior coherence of narrow-bandwidth self-seeded X-ray pulses significantly improves the quality and reliability of image reconstruction in coherent diffraction imaging compared with conventional broad-bandwidth SASE pulses. These findings highlight the critical role of spectral purity in achieving high-fidelity lensless imaging with X-ray free-electron lasers.
Integrated control of a nanoindenter and X-ray nanodiffraction for automated in situ nanomechanical studies
X-ray diffraction (XRD) combined with in situ mechanical testing is a powerful, non-destructive technique that provides valuable information on structural evolution and defect formation during deformation. Unlike many other characterization methods, XRD does not impose constraints on sample dimensions, does not require a vacuum environment, and can be applied to a wide range of materials with periodic structures. However, such experiments present significant challenges due to the need for precise synchronization between independently controlled systems: one managing mechanical loading and the other handling X-ray measurements. In this work, we report on the successful software-level integration of a nanoindenter control system directly into the beamline control system. This integration enables full control of both mechanical and diffraction measurements from a single user interface, allowing real-time synchronization and automation of complex in situ experiments. We demonstrate the capabilities of this setup through uniaxial compression tests on α-Ti micropillars. Mechanical data from the nanoindenter and XRD patterns were collected simultaneously in an automated mode. Raster scans were performed on the micropillar in its pristine state, at two intermediate deformation stages, and post-mortem. This approach enabled detailed analysis of mechanical behavior and structural evolution under load, illustrating the effectiveness of the integrated system for advanced in situ studies.
This work presents a software-level integration of nanoindenter control directly into a beamline control system, enabling fully synchronized and automated in situ experiments through unified, real-time coordination of mechanical loading and X-ray nanodiffraction measurements.
Mobile electromagnetic levitator for time-resolved in situ X-ray diffraction studies of high-temperature phase transformations
In situ observations of high-temperature transformations, not compromised by reactivity with a crucible, have recently become accessible by integrating containerless processing with the time-resolved diffraction of synchrotron X-rays. The presented electromagnetic levitator (EML) has been designed for mobility and ease of operation during beamline experiments while enabling stable processing of a wide range of materials. Developed to work with area detectors, the facility's capabilities are demonstrated by measurements of the structural changes during melting and solidification of pure Fe and Fe–Co samples. The direct observations of the metastable phase formation in the Fe–Co system, accessible through containerless processing, have been accomplished for the first time due to the improved acquisition rate of modern area detectors. The diffraction patterns and associated artifacts characteristic of crystal structure measurements during levitation are examined. Moreover, an analytical description of the measured instrumental resolution of the diffraction setup is presented along with a survey of the corrections and associated measurements necessary for an accurate total scattering analysis of the disordered states, such as liquids or glasses. This provides a base for the conceptual planning of diffraction experiments suitable for various levitation methods, including electrostatic, aerodynamic and acoustic levitation.
A mobile electromagnetic levitator combined with time-resolved synchrotron X-ray diffraction enables in situ studies of high-temperature phase transformations without container-induced contamination and reveals the first direct observation of metastable phase formation in undercooled Fe–Co alloys.
Effect of oxygen and nanoparticles on human skin and colon cells exposed to synchrotron-based X-ray FLASH beams
FLASH radiotherapy involves delivering relatively high radiation doses at ultra-high dose rates (UHDRs) that are several orders of magnitude greater than those used in conventional radiotherapy (40 Gy s−1 versus 0.5–5 Gy min−1, respectively). Previous in vivo studies have shown that doses delivered with such UHDRs result in significant tumour killing while having less effect on normal tissues. Most of these in vivo studies were based on the use of charged particles such as electrons and protons. In this study we exposed cells [human epidermal melanocytes (HEM), MM96L melanoma cells, CCD841 colon epithelial cells and CaCo2 colorectal adenocarcinoma cells] grown in vitro to synchrotron-based X-ray beams delivered at either low dose rates or UHDRs to validate the FLASH effect. The FLASH effect that has been reported to occur under hypoxic conditions was also investigated using HEM and MM96L cells. Significant cell killing was observed at 48 h post-irradiation, when the cells were exposed to high dose (≥10 Gy) UHDRs compared with low dose rate beams in both groups of cells. MM96L melanoma cells were ∼10% less resistant to UHDR than were HEM cells. A similar result was observed in CCD841 and CaCo2 cells. When the hypoxic melanocytes were exposed to (≥10 Gy) UHDRs a minimal loss of cell viability was observed; however, when hypoxic MM96L cells were irradiated, significant cell losses were observed. These results show that a FLASH effect is evident in these skin and colon cells. Moreover, when MM96L melanoma cells were pretreated with 1 mM gold nanoparticles and exposed to 10 Gy UHDR X-rays there was a 50% dose enhancement observed where only 15% was observed at low dose rates.
Most cancer patients will be treated by radiotherapy, and recent findings suggest that delivering radiation at `FLASH' ultra-high dose rates reduces damage to healthy tissues while still damaging the tumour. This project experimentally validates the reduced healthy tissue damage of FLASH radiotherapy on cells using synchrotron-based beams, which will support future clinical trials and ultimately leading to its application in cancer treatment.
Shaped electrodes for adaptive X-ray optics
Lithium niobate has emerged as a promising substrate material for adaptive X-ray mirrors. Heat treatment induces ferroelectric domain inversion, yielding two oppositely poled, layered regions that enable lithium niobate to behave as a monolithic bimorph in the presence of an applied electric field. In addition to fabrication simplicity, this well known material has favorable actuation and shape-control properties without hysteresis, creep, and drift. Following Timoshenko's approach to the bi-metallic strip thermostat, we derive an analytic description of shaping continuous electrode widths to produce a spatially varying surface curvature when a voltage is applied. Through comparison with finite-element analysis, the method is demonstrated for uniform electrode widths that produce cylindrical surfaces, and for varying electrode widths that produce plane-parabolic and plane-elliptical surfaces from initially flat substrates. A proposed longitudinally continuous, compound electrode pattern shows how a single flat mirror could be shaped to achieve multiple profiles with a single applied voltage.
For adaptive X-ray optics on high-performance beamline optical systems, we describe an approach to mirror figure and slope control using patterned, shaped electrodes to control the local curvature on a lithium niobate substrate from a single applied voltage. Longitudinally continuous electrode patterns achieve target shapes without discontinuities, and compound electrodes enable multiple target shapes to be achieved on a single substrate.
Gepta-EX: a multi-channel germanium detector for X-ray absorption fine structure
Fluorescence-mode X-ray absorption spectroscopy (XAS) at high photon energies requires detectors with high stopping power and excellent energy resolution to measure weak element-specific signals. Traditional silicon-based detectors suffer from poor efficiency above ∼20 keV, while most high-Z materials such as cadmium telluride, cadmium zinc telluride, and gallium arsenide have focused predominantly on imaging applications with limited spectroscopic resolution. In contrast, germanium combines excellent stopping power with superior intrinsic energy resolution due to its low Fano factor and favorable charge transport properties, making it ideal for high-resolution spectroscopy in the 15 keV to 100 keV range. To address these requirements, we report on the development, fabrication, and performance evaluation of Gepta-EX, a compact multi-channel high-purity germanium (HPGe) detector system for fluorescence-mode XAS. The Gepta-EX system features a monolithic seven-channel HPGe pixel array integrated with low-noise CUBE charge-sensitive preamplifiers, housed within a thermally isolated compact cryostat operating near 90 K. The detector achieves energy resolutions of 218 eV at 5.9 keV (from a 55Fe source) and 373 eV at 59.5 keV (from a 241Am source), with uniform performance across all channels. By avoiding the escape peak interference commonly associated with silicon detectors and providing stable, high-resolution performance, Gepta-EX represents a powerful tool for high-energy X-ray spectroscopy.
Gepta-EX is a compact seven-channel high-purity germanium detector designed to deliver high-resolution fluorescence X-ray absorption fine-structure measurements at photon energies where silicon detectors become effectively transparent. It provides excellent energy resolution across a broad energy range, avoids silicon escape-peak artifacts, and offers uniform multi-channel performance, enabling reliable high-energy X-ray absorption studies of advanced materials.
GIWAXS using microbeam applied in halide perovskite films for high spectral resolution and mapping capability
Synchrotron-based grazing-incidence wide-angle X-ray scattering (GIWAXS) has become an essential tool for investigating halide perovskite film microstructures. Nevertheless, GIWAXS employing 100 µm X-ray beams inevitably suffers from footprint effects manifesting as diffraction peak broadening and spectral distortions. Herein, we demonstrate that microbeam GIWAXS (µ-GIWAXS) effectively mitigates these footprint effects, achieving enhanced spectral resolution and accuracy. By systematically tuning the grazing incidence angle, we quantitatively illustrated how the footprint length contributes to diffraction peak broadening in µ-GIWAXS. In addition, we optimize µ-GIWAXS data acquisition through beam-direction-perpendicular fly scanning, which improves data quality while preserving resolution and minimizing radiation damage at individual spots. Through extended exposure experiments, the effect of µ-GIWAXS microbeam irradiation on the structural stability of perovskite films was systematically evaluated. Furthermore, µ-GIWAXS enables spatial mapping of perovskite film microstructural characteristics including crystallinity, preferential crystal orientation, PbI2 concentration and lattice strain – critical information for addressing inhomogeneity challenges in large-area perovskite devices. Given the growing demand in scalable perovskite optoelectronic applications, µ-GIWAXS warrants increased attention due to its dual advantages of superior spectral resolution and spatially resolved analysis capabilities.
This article demonstrates that microbeam GIWAXS (µ-GIWAXS) effectively overcomes the distorting footprint effects of conventional GIWAXS analysis of perovskite films. This advancement not only delivers higher reciprocal-space resolution data but also unlocks the unique capability to spatially map microstructural inhomogeneity, which is vital for the scalable manufacturing of perovskite optoelectronics.
Simultaneous measurements of solid–liquid interfaces and bulk liquids using soft X-ray absorption spectroscopy
Simultaneous measurement methods for soft X-ray absorption spectroscopy (XAS) of solid–liquid interfaces and bulk liquids have been developed. The O K-edge XAS spectra of H2O/Au interfaces and bulk H2O were measured using a transmission-type liquid cell, in which the liquid layer was sandwiched between Au/Cr/Si3N4 and Si3N4 membranes. The XAS spectrum of bulk H2O was obtained using the transmission method by controlling the thickness of the liquid layer, whereas the XAS spectrum of the H2O/Au interface was obtained using the electron-yield method by measuring the drain currents from the Au surface after soft X-ray absorption. The XAS spectra of bulk H2O and the H2O/Au interfaces were differentiated to determine the appropriate measurement conditions for the solid–liquid interfaces interfaces.
Simultaneous measurement methods have been developed for soft X-ray absorption spectroscopy of solid–liquid interfaces using the electron-yield method and bulk liquids using the transmission method.
Full-field X-ray fluorescence imaging using a Fresnel zone plate as a coded aperture: optimized reconstruction algorithm and first trial of hyperspectral XANES mapping
This study represents the first feasibility demonstration of hyperspectral X-ray absorption near-edge structure (XANES) mapping performed using a full-field fluorescence imaging approach. This method may be useful in many research fields for determining the spatial distributions of the different oxidation states of an element present at low concentration in X-ray beam-sensitive samples. It was demonstrated that this approach could be easily performed using a full-field imaging method where a Fresnel zone plate (FZP) was employed as a coded aperture, which represented a practical, fast and dose-efficient alternative to the raster-scanning technique, when these two approaches were tested at a beamline not dedicated to X-ray imaging. The basic form of the reconstruction algorithm, which was derived from inline holography, was optimized. This enabled the spatial resolution and overall quality of the reconstructed image to be improved. The ∼62 µm spatial resolution experimentally achieved may be further optimized to about 5 µm using a smaller FZP and larger detector than those used in this investigation. The XANES spectra corresponding to the main chemical species present in the sample, obtained from the tested hyperspectral spectroscopy approach, did not exactly match those expected, as they depended on several empirical processing steps. While these results can be further improved by optimizing the linearity of the detector output via pile-up corrections, further work is needed to establish robustness against variations in masking, background treatment, and intensity-correction choices, especially for studying diluted specimens whose corresponding pixel intensities are similar to those of the background.
The full-field X-ray fluorescence imaging method, where a Fresnel zone plate is employed as a coded aperture, was tested for the first time at a beamline, and its corresponding reconstruction code was optimized. It was also employed to perform, also for the first time using full-field and fluorescence modes, hyperspectral XANES mapping.
spatial determination of oxydation states
Synchrotron beamline setup enabling quasi-simultaneous PXRD and XANES measurements: case study of Fischer–Tropsch catalyst reduction at 60 bar
Powder X-ray diffraction (PXRD) and X-ray absorption near-edge structure (XANES) spectroscopy are complementary techniques for probing cobalt-based (Co-based) Fischer–Tropsch synthesis (FTS) catalyst structures. PXRD reveals crystalline composition, while XANES provides information on coordination geometry and oxidation state. We developed a fast, automated measurement method, based on rapid selection of X-ray beam energy and a dedicated sample environment at beamline ID10 (ESRF), to combine in situ PXRD and XANES in a single experiment. This approach enables simultaneous monitoring of structural and electronic changes in Co-based FTS catalysts under in situ conditions up to 60 bar, offering a comprehensive view of catalyst dynamics.
This paper presents a beamline setup that allows the combination of in situ powder X-ray diffraction (PXRD) and X-ray absorption near-edge structure (XANES) measurements within a single experimental cycle to investigate cobalt catalyst structures and properties under real conditions.
Distributed computing for the reconstruction of multi-terabyte tomographic X-ray imaging datasets
Tomographic datasets have continued to grow in size and volume along with camera technology and synchrotron brilliance. These larger datasets require new methods of distributing the reconstruction process on high-performance computing systems. Here we present a program for reconstructing large datasets, allowing the usage of either CPU- or GPU-powered clusters, and show the successful reconstruction of a 24000 pixel-wide dataset. This program is currently in use at the DanMAX beamline at the MAX IV synchrotron and is used as the default reconstruction method for all tomographic experiments at the beamline. Scans reconstructed with the presented pipeline have been published in multiple journals.
As tomographic datasets from synchrotrons continue to increase in volume, so rises the challenge of reconstructing said data. Here we present a solution utilizing high-performance computing capabilities to split the process into multiple smaller tasks, which can be solved without overwhelming a single compute node. This solution is currently in use at the DanMAX beamline at the MAX IV synchrotron.
Paired CycleGAN-based virtual staining for 3D X-ray histology of bone-implant systems
Three-dimensional X-ray histology offers a non-invasive alternative to conventional 2D histology, enabling volumetric imaging of biological tissues without physical sectioning or chemical staining. However, the intrinsic greyscale contrast of X-ray tomography limits its biochemical specificity compared with traditional histological stains. In this study, we extend deep-learning-based virtual staining to the X-ray domain via cross-modality image translation to generate artificially stained slices directly from synchrotron radiation microtomography (µCT) scans. Using over 50 co-registered pairs of µCT and toluidine blue-stained histology from bone-implant samples, we trained a modified CycleGAN network tailored for limited paired data. Whole-slide histology images were downsampled to the CT voxel size, with on-the-fly data augmentation for patch-based training. The model incorporates pixelwise supervision and greyscale consistency losses, enabling histologically realistic colour outputs while preserving structural detail. Results outperformed Pix2Pix and standard CycleGAN baselines across metrics of structural similarity, perceptual fidelity, and peak signal-to-noise ratio. Once trained, the model can be applied to full µCT volumes to produce virtually stained 3D datasets that enhance interpretability without additional sample preparation. This work introduces virtual staining to 3D X-ray imaging, which may provide a scalable route for chemically informative, label-free tissue characterization in biomedical research.
This work demonstrates virtual staining for 3D X-ray histology using a modified CycleGAN trained on paired synchrotron radiation microtomography (SR-µCT) and histology images of bone-implant specimens. The method enables the generation of artificially coloured contrast resembling conventional histological staining from label-free SR-µCT data and is scalable across entire 3D volumes without additional sample preparation.
High/low temperature setups for submillimetric samples under various extreme conditions at the AILES beamline
Infrared and terahertz spectroscopy performed at synchrotron facilities offers unique opportunities for probing matter under extreme and well controlled conditions. At the AILES beamline of Synchrotron SOLEIL, two complementary experimental setups have recently been developed to enable spectroscopy of submillimetric samples across a broad range of temperatures and pressures. These platforms operate from 10 K to 600 K and from vacuum up to 100 GPa, while accommodating a variety of sample environments, including liquid cells, diamond anvil cells and uniaxial strain devices. Combined with the high brilliance and stability of synchrotron radiation and advanced detection schemes, these setups are particularly suited for in situ and operando investigations, allowing real-time monitoring of structural changes, phase transitions and reaction dynamics under external stimuli. Their performance is illustrated through far-infrared measurements of water and ice over different thermodynamic states, demonstrating sensitivity to structural reorganizations and hydrogen-bond dynamics. These developments significantly expand the experimental capabilities of the AILES beamline and provide versatile tools for a wide user community, opening new perspectives for studies of functional materials, molecular systems and emerging phenomena under extreme conditions.
Two complementary high- and low-temperature experimental setups have been developed at the AILES beamline of Synchrotron SOLEIL to enable infrared and terahertz spectroscopy of submillimetric samples under extreme and well controlled pressure and temperature conditions (from 10 K to 600 K and from vacuum up to 100 GPa). The ensembles are compatible with a variety of sample environments, as liquid cells, diamond anvil cells and uniaxial strain devices.
An induction heating system for in situ X-ray diffraction imaging: design, simulation and application to dislocation dynamics in semiconductors
We present a compact induction heating system for time-resolved in situ X-ray diffraction imaging, enabling contact-free volumetric heating of samples up to approximately 1600°C with flexible operation in different working modes. Real-time, spatially resolved thermography is achieved using an integrated near-infrared camera. A three-dimensional finite-element model of electromagnetic heating, steady-state heat transfer and thermo-elastic stress predicts Joule heating, temperature fields and resolved shear stresses, and guides experimental design. The system has been demonstrated at a synchrotron topography station using simultaneous X-ray white-beam topography and infrared thermography during controlled heating of an indented Si(001) wafer. Dislocation activity is observed starting at local temperatures above 1000°C, increasing at higher temperatures. The experimentally observed number of dislocations on individual {111}〈110〉 glide systems correlates with the simulated resolved shear stresses. This integrated approach enables quantitative, time-resolved studies of dislocation dynamics under well defined thermal conditions and offers a simulation-guided route to tailoring temperature gradients and stress fields for future materials and in situ experiments.
This work presents a compact induction heating system for time-resolved in situ X-ray diffraction imaging. The system enables contact-free volumetric heating up to approximately 1600°C and provides flexible operation in different operating modes. Its performance is demonstrated through representative diffraction imaging experiments.
Air attenuation of high power XFEL beams
The Linac Coherent Light Source II, a high-repetition-rate X-ray free-electron laser (FEL), produces high average power as well as high peak power. Air is a key radiation safety element, helping to contain the FEL beams from reaching accessible areas. At high average power, air absorption can produce a high-temperature and low-density channel along the X-ray beam path. In this case, the X-ray attenuation no longer follows the Beer–Lambert equation, exp(−μx). Air attenuation measurements were performed with X-rays focused into a gas cell at the LCLS time-resolved AMO instrument. In the measurements, several parameters were varied: the repetition rate from 102 Hz to 33.2 kHz, the pulse energy from 18 to 340 µJ and the photon energy at 316 and 346 eV. The air transmission was observed to significantly increase with X-ray power. Simulations were also performed, which included the thermal processes related to the high average power. In comparison with the measurements, the calculated air transmission is higher, confirming that the simulations are conservative and suitable for radiation safety analyses.
The transmission of air, which is used to contain X-ray beams for radiation safety, is observed to significantly increase with X-ray power.
Design and commissioning of a new synchrotron beamline dedicated to X-ray footprinting mass spectrometry
The structural biology method of X-ray footprinting mass spectrometry (XFMS) is available at two national synchrotron beamlines in the USA: one at the Advanced Light Source (ALS) on the West Coast and the other at the National Synchrotron Light Source II on the East Coast. XFMS is a solution-state technique that utilizes oxidative modifications of proteins at micromolar concentrations in aqueous buffer to extract structural information. X-rays are employed to generate hydroxyl radicals in situ, which covalently modify specific protein side chains. These modifications are subsequently quantified using liquid chromatography and mass spectrometry. Ratiometric changes in modification levels between two protein states (e.g. with and without ligand) generate a relative solvent accessibility map of the protein pairs, which serves to reveal structural features. Up until recently, the XFMS capability was available as part of a shared program at the ALS without a dedicated beamline. In this article, we describe the commissioning of ALS beamline 3.3.1, dedicated to XFMS, including the installation of a new focusing mirror, the design and construction of a new endstation with automated sample handling and exposure capabilities, and the use of accurate empirical dose calculations using Gafchromic film. Finally, we showcase the new beamline capabilities using two protein systems.
A dedicated beamline at the Advanced Light Source synchrotron has been opened and commissioned for X-ray footprinting mass spectrometry.
X-ray footprinting mass spectrometry (XFMS)
Liquid jet capabilities for ultrafast chemistry at the SwissFEL Alvra instrument
The Alvra experimental station at the Swiss X-ray free-electron laser, SwissFEL, investigates ultrafast dynamics in chemical and biological systems using X-ray scattering and spectroscopy techniques. A key feature of Alvra is its unique capability to perform time-resolved X-ray emission and resonant inelastic X-ray scattering in the tender X-ray regime, currently not available at other XFEL endstations, combined with simultaneous access to X-ray absorption spectroscopy and X-ray solution scattering. Together with sub-35 fs time resolution enabled by advanced timing diagnostics, this positions Alvra as a versatile instrument for ultrafast chemical dynamics in the liquid phase. Here we cover the various technical aspects of the beamline and experimental station, and present some examples of experimental results measured during the first years of SwissFEL commissioning and user operation.
The technical aspects of the Alvra endstation are outlined and its scientific capabilities are demonstrated with commissioning results obtained during the early years of SwissFEL's operation.