Journal of Synchrotron Radiation最新文献

X-ray imaging is a powerful technique to scan samples in a variety of contexts including biological, environmental and materials science, but commonly requires a synchrotron light source to produce X-rays at sufficient intensity. As these facilities are expensive to operate, the available beam time is limited and always in high demand. Particularly if the illuminated samples are sparse, standard raster scanning methods can be time-consuming, with a majority of that time being spent on areas of the image that carry little information. To increase the efficiency and maximize the information gain for a given time budget, we split the scanning process into a series of steps where previous measurements are used to inform the decision making and adapt the exposure distribution at later stages of the sequence. We formulate this task as a reinforcement learning problem where the goal is to produce a sequence of exposure maps that maximize a predefined scalar metric. We demonstrate the potential of this approach in simulations where the adaptive illumination can accelerate the measurement process by up to an order of magnitude compared with standard raster scanning. Finally, we present the first results from deploying the trained agents on an X-ray fluorescence beamline at the Stanford Synchrotron Radiation Lightsource.

We provide a historical introduction spanning the past 50 years of synchrotron radiation protein crystallography. We then provide a resume of current trends. These help us to celebrate the huge influence that synchrotron radiation, and now X-ray lasers, has had on the scope of protein crystallography. It has also accelerated the development of closely allied methods such as neutron protein crystallography, which has adopted the synchrotron Laue method as its own as well as developing monochromatic and time-of-flight methods. Also, the democratic access to central synchrotron facility beamlines has prompted similarly operated centres of electron cryo-microscopy and micro-electron diffraction. We offer our thoughts on the current trends across this scientific landscape.

Synchrotron X-ray structural biology has developed into a worldwide, highly productive enterprise whose capabilities are providing thousands of users annually with the means to make innovative and outstanding scientific discoveries based on biological structure and function, impacting areas of human health, bioenergy and sustainability and many others. This special virtual issue of Journal of Synchrotron Radiation (https://journals.iucr.org/special_issues/2025/ssrlprotein) includes a series of contributed papers from scientists at structural biology synchrotron centers worldwide that describe capabilities, scientific discoveries and future directions. In my article, I will start with a focus on the first macromolecular crystallography studies at SSRL that were published in 1976, followed by developments in anomalous scattering and multi-wavelength phasing. I will then highlight some technology and methodology developments including X-ray detectors and beamline automation, which were key in building robust, sustainable resources at SSRL and other synchrotron radiation facilities for the structural biology user community. I will highlight other related elements including accelerator R&D, consider some of the overarching factors which I believe have been important for the sustained success and growth of this enterprise for 50 years and counting, and highlight some of the indicators of the enormous success of this venture. Throughout I will comment upon some of the new developments and trends that are emerging.

In this paper, we introduce the Modular Adaptive Processing Infrastructure (MAPI), a comprehensive software suite and approach designed to streamline and enhance data analysis workflows in scientific research laboratories. MAPI selects and integrates multiple frameworks and toolkits into a web-based platform, offering a highly modular and adaptable solution for diverse data analysis requirements. By design, MAPI supports distributed processing across heterogeneous backends (edge workstations, on-premises servers, high-performance computing and public cloud), making it suitable for various beamlines and data-processing labs. This blueprint, or `recipe', provides a flexible infrastructure that can be tailored to specific experimental needs. We showcase MAPI's application through its successful implementation on the X-ray computed tomography (CT) beamline, resulting in a system for tomographic processing (STP3). The case study demonstrates MAPI's effectiveness in meeting complex computational demands, highlighting its potential for widespread adoption in scientific research environments. Most of the results reported in the paper are from a production deployment on Elettra's SYRMEP beamline using two on-premises GPU servers, but two additional ongoing deployments on different beamlines are discussed.

The hard X-ray beamline (Aramis) of the Swiss free-electron laser (SwissFEL) has been in user operation since the end of 2017 and its performance has been continuously monitored and enhanced over the past eight years. From the beginning, spontaneous radiation has been utilized to monitor the behavior of its 13 individual undulator modules: the pointing direction of the electron beam in each module, their alignment relative to the electron beam, and the calibration of their magnetic field strength (K calibration). This article introduces the methods employed at the Aramis beamline to optimize performance using spontaneous radiation, traces the evolution of these improvements, and highlights the recently achieved record performance.

A newly developed four-segmented APPLE-II undulator enables arbitrary polarization control in the soft to tender X-ray region. The undulator is installed at NanoTerasu BL13U, aiming for X-ray absorption spectroscopy over a wide energy range, 180-3000 eV, with versatile photon polarizations. By adjusting the phase difference of the synchrotron radiation using electromagnetic phase shifters, arbitrary orientations of linear polarization were obtained from left and right circularly polarized radiation. Elliptically polarized radiation was also generated from vertical and horizontal linearly polarized radiation. In addition, the ellipticity angles were successfully controlled. Circularly polarized radiation in the tender X-ray region is considered to be achieved by utilizing the third harmonic. Methods and performance of polarization control of the segmented APPLE-II undulator using the phase shifters are presented.

The total energy resolution (ΔE_tot) of a valence-band resonant inelastic X-ray scattering (VB-RIXS) instrument serves as an important point of reference in an otherwise complex field. Since VB-RIXS is a flux-limited technique, a pragmatic approach to reducing ΔE_tot is often required-the specifications of a spectrometer should be matched with a comparable incident bandwidth (ΔE_i) and the source size contribution (focal point) should be negligible. Although it advocates for a good efficiency, this approach is in many places already limited by count-rates. Here we follow a recent trend emerging in soft X-ray VB-RIXS and look at the performance of our tender X-ray Rowland spectrometer (Gretarsson et al., 2020) when being exposed to a source with a large linear dispersion (higher flux). Detailed ray tracing work, performed at the U M₅-edge (3551 eV), finds that the intrinsic resolution of the Rowland spectrometer (ΔE_a) can be obtained if the linear dispersion of the source matches the spectrometer's, but opposite in sign-here ΔE_i does not matter. This finding is supported by experimental data where ΔE_tot = 48 meV (ΔE_a = 44 meV) was recently achieved. Furthermore, we demonstrate that the dispersion rate can be tuned, ensuring the method's applicability to other atomic edges.

X-ray fluorescence (XRF) is a popular spectroscopy technique for elemental analysis. Spectrum fitting and parameter tuning are at the core of XRF analysis and are conventionally manually intensive, especially for synchrotron experiments involving large amounts of diverse samples. This work introduces the automatic differentiation (AD) technique to XRF and an open-source package called MapsTorch. By transforming an analytical model of the XRF spectrum into a differentiable computation graph with AD, MapsTorch enables robust optimization of parameters and elemental intensities. We evaluate MapsTorch by conducting computational experiments on a large number of historical synchrotron XRF datasets and compare its performance with the currently practiced fitting tool NLopt. The results show that MapsTorch consistently achieves high-quality fits and often leads to better fitting quality than NLopt, particularly in tasks such as initial spectrum fitting and elemental intensity refinement. The robust performance of MapsTorch paves the way for developing automated and high-throughput XRF data analysis workflows to handle the increasing data volumes expected from next-generation synchrotron facilities.

Due to their superior fatigue strength, martensitic steels are the material of choice for high cyclic loading applications such as coil springs. However, crack propagation is influenced by residual stresses and their interaction is poorly understood. In fact, linear elastic fracture mechanics predicts unphysical singularities in the strain around the crack tip. In this study, we have combined synchrotron-based X-ray diffraction, X-ray fluorescence and optical microscopy to map the factual strain fields around crack tips with micrometre spatial resolution. X-ray fluorescence and optical images were co-registered to locate the crack in the X-ray diffraction maps. Observed crystal recovery close to cracks confirmed that the diffraction signal originates at least in part from the cracks. The retrieved local strain field around the crack was further improved by averaging information over carefully selected diffraction peaks. This procedure provided strain maps around crack tips with a spatial resolution of about 1 µm and may enable heuristic predictions of further crack growth.

The BL46XU beamline of SPring-8 has been reorganized into a beamline dedicated to hard X-ray photoelectron spectroscopy (HAXPES) to meet the increasing demand for various HAXPES based measurements. Two specialized HAXPES instruments, namely, (i) a high-throughput HAXPES system specialized for automated measurements and (ii) an ambient pressure HAXPES system with a focus on measurements under a gas atmosphere, provide advanced capabilities for characterizing bulk-sensitive electronic and chemical states in a variety of research fields. To enhance the capabilities further, several X-ray optical instruments have been introduced. Two types of double channel-cut monochromators [Si(220) and Si(311)] have been installed in the optics hutch, allowing users to select the optimum energy resolution and flux in a wide photon-energy range (4.9-21.8 keV) while keeping a fixed-exit condition. In addition, a focusing mirror to provide a high-flux microbeam has been arranged for each HAXPES system. In this article, the design and performance of the beamline as well as some recent scientific results are outlined.