Search

Ultraviolet and vacuum ultraviolet photo-absorption spectra of azido (–N3)-based energetic plasticizer, bis(1,3-diazido-prop-2-yl)-malonate (abbreviated as BDAzPM), in the gas phase is recorded at room temperature and in the photon energy range of 5.5–9.9 eV using a synchrotron radiation source. Complementary computational results obtained using the time-dependent density functional theory document the vertical transition energies and oscillator strengths. Comparison of the simulated spectra with the experimental absorption spectrum of BDAzPM reveals that the early part of the absorption spectrum of BDAzPM is of pure valence excitation character, whereas the later intense part of the absorption spectrum is dominated by mixed Rydberg and valence electronic excitations. [ABSTRACT FROM AUTHOR]

The paper considers the possibility of using the diamond‐silicon carbide composite Skeleton® with a technological coating of polycrystalline silicon as a substrate for X‐ray mirrors used with powerful synchrotron radiation sources (third+ and fourth generation). Samples were studied after polishing to provide the following surface parameters: root‐mean‐square flatness ≃ 50 nm, micro‐roughness on the frame 2 µm × 2 µm σ ≃ 0.15 nm. The heat capacity, thermal conductivity and coefficient of linear thermal expansion were investigated. For comparison, a monocrystalline silicon sample was studied under the same conditions using the same methods. The value of the coefficient of linear thermal expansion turned out to be higher than that of monocrystalline silicon and amounted to 4.3 × 10−6 K−1, and the values of thermal conductivity (5.0 W cm−1 K−1) and heat capacity (1.2 J K−1 g−1) also exceeded the values for Si. Thermally induced deformations of both Skeleton® and monocrystalline silicon samples under irradiation with a CO2 laser beam have also been experimentally studied. Taking into account the obtained thermophysical constants, the calculation of thermally induced deformation under irradiation with hard (20 keV) X‐rays showed almost three times less deformation of the Skeleton® sample than of the monocrystalline silicon sample. [ABSTRACT FROM AUTHOR]

Achieving diffraction‐limited performance in fourth‐generation synchrotron radiation sources demands monochromator crystals that can preserve the wavefront across an unprecedented extensive range. There is an urgent need for techniques of absolute crystal diffraction wavefront measurement. At the Beijing Synchrotron Radiation Facility (BSRF), a novel edge scan wavefront metrology technique has been developed. This technique employs a double‐edge tracking method, making diffraction‐limited level absolute crystal diffraction wavefront measurement a reality. The results demonstrate an equivalent diffraction surface slope error below 70 nrad (corresponding to a wavefront phase error of 4.57% λ) r.m.s. within a nearly 6 mm range for a flat crystal in the crystal surface coordinate. The double‐edge structure contributes to exceptional measurement precision for slope error reproducibility, achieving levels below 15 nrad (phase error reproducibility < λ/100) even at a first‐generation synchrotron radiation source. Currently, the measurement termed double‐edge scan (DES) has already been regarded as a critical feedback mechanism in the fabrication of next‐generation crystals. [ABSTRACT FROM AUTHOR]

The article investigates how the lncRNA Sera and the Pkm2 pathway in the medial prefrontal cortex (mPFC) affect social competition and rank by remodeling neural ensembles in mice. Topics discussed include the role of the Sera/Pkm2 pathway in competitive success, the modulation of excitatory neurons in the prelimbic cortex, and the phosphorylation of AMPA receptors influencing social rank.

The present study evaluated the repercussions of magnetopriming on the root system architecture of soybean plants subjected to arsenic toxicity using synchrotron radiation source based micro-computed tomography (SR-µCT). This will be used evey where as abbreviation for the technique for threedimensional imaging. Seeds of soybean were exposed to the static magnetic field (SMF) of strength (200 mT) for 1h prior to sowing. Magnetoprimed and nonprimed seeds were grown for 1 month in a soil-sand mixture containing four different levels of sodium arsenate (0, 5, 10, and 50 mg As kg-1 soil). The results showed that arsenic adversely affects the root growth in non-primed plants by reducing their root length, root biomass, root hair, size and number of root nodules, where the damaging effect of As was observed maximum at higher concentrations (10 and 50 mg As kg-1 soil). However, a significant improvement in root morphology was detected in magnetoprimed plants where SMF pretreatment enhanced the root length, root biomass, pore diameter of cortical cells, root hair formation, lateral roots branching, and size of root nodules and girth of primary roots. Qualitative analysis of x-ray micro-CT images showed that arsenic toxicity damaged the epidermal and cortical layers of the root as well as reduced the pore diameter of the cortical cells. However, the diameter of cortical cells pores in magnetoprimed plants was observed higher as compared to plants emerged from non-primed seeds at all level of As toxicity. Thus, the study suggested that magnetopriming has the potential to attenuate the toxic effect of As and could be employed as a pre-sowing treatment to reduce the phytotoxic effects of metal ions in plants by improving root architecture and root tolerance index. This study is the very first exploration of the potential benefits of magnetopriming in mitigating the toxicity of metals (As) in plant roots utilizing the micro-CT technique. [ABSTRACT FROM AUTHOR]

With the continuous development of synchrotron radiation light sources, higher requirements have been put forward for the stability of double-crystal monochromators in synchrotron radiation facilities. This paper designs an active adjustment mechanism for a double-crystal monochromator to improve its stability. Firstly, three spatial degrees of freedom are designed based on the active adjustment mechanism of flexible leaf spring parallel coupling, and the prototype of the mechanism is fabricated. Secondly, system identification experiments are carried out and the system transfer function curve is fitted by the nonlinear least squares method. Thirdly, the controller based on non-singular terminal sliding modes and a finite-time disturbance observer was designed for stability control and disturbance compensation. Finally, the effectiveness of the controller is verified by a model-in-the-loop approach based on the performance of the real-time target machine. The results show that the non-singular terminal sliding mode + finite-time disturbance observer control strategy can reduce the RMS value of the vibration displacement of Axis-1/Axis-2/Axis-3 by 81.25%, 78.53%, and 71.82%. [ABSTRACT FROM AUTHOR]

Understanding and controlling the structure and function of liquid interfaces is a constant challenge in biology, nanoscience and nanotechnology, with applications ranging from molecular electronics to controlled drug release. X‐ray reflectivity and grazing incidence diffraction provide invaluable probes for studying the atomic scale structure at liquid–air interfaces. The new time‐resolved laser system at the LISA liquid diffractometer situated at beamline P08 at the PETRA III synchrotron radiation source in Hamburg provides a laser pump with X‐ray probe. The femtosecond laser combined with the LISA diffractometer allows unique opportunities to investigate photo‐induced structural changes at liquid interfaces on the pico‐ and nanosecond time scales with pump–probe techniques. A time resolution of 38 ps has been achieved and verified with Bi. First experiments include laser‐induced effects on salt solutions and liquid mercury surfaces with static and varied time scales measurements showing the proof of concept for investigations at liquid surfaces. [ABSTRACT FROM AUTHOR]

With the development of serial crystallography at both x-ray free electron laser and synchrotron radiation sources, time-resolved x-ray crystallography is increasingly being applied to study conformational changes in macromolecules. A successful time-resolved serial crystallography study requires the growth of microcrystals, a mechanism for synchronized and homogeneous excitation of the reaction of interest within microcrystals, and tools for structural interpretation. Here, we utilize time-resolved serial femtosecond crystallography data collected from microcrystals of bacteriorhodopsin to compare results from partial occupancy structural refinement and refinement against extrapolated data. We illustrate the domain wherein the amplitude of refined conformational changes is inversely proportional to the activated state occupancy. We illustrate how resampling strategies allow coordinate uncertainty to be estimated and demonstrate that these two approaches to structural refinement agree within coordinate errors. We illustrate how singular value decomposition of a set of difference Fourier electron density maps calculated from resampled data can minimize phase bias in these maps, and we quantify residual densities for transient water molecules by analyzing difference Fourier and Polder omit maps from resampled data. We suggest that these tools may assist others in judging the confidence with which observed electron density differences may be interpreted as functionally important conformational changes. [ABSTRACT FROM AUTHOR]

With the development of synchrotron radiation sources and high-frame-rate detectors, the amount of experimental data collected at synchrotron radiation beamlines has increased exponentially. As a result, data processing for synchrotron radiation experiments has entered the era of big data. It is becoming increasingly important for beamlines to have the capability to process large-scale data in parallel to keep up with the rapid growth of data. Currently, there is no set of data processing solutions based on the big data technology framework for beamlines. Apache Hadoop is a widely used distributed system architecture for solving the problem of massive data storage and computation. This paper presents a set of distributed data processing schemes for beamlines with experimental data using Hadoop. The Hadoop Distributed File System is utilized as the distributed file storage system, and Hadoop YARN serves as the resource scheduler for the distributed computing cluster. A distributed data processing pipeline that can carry out massively parallel computation is designed and developed using Hadoop Spark. The entire data processing platform adopts a distributed microservice architecture, which makes the system easy to expand, reduces module coupling and improves reliability. [ABSTRACT FROM AUTHOR]

Angle-resolved photoemission spectroscopy (ARPES) is a technique used to map the occupied electronic structure of solids. Recent progress in x-ray focusing optics has led to the development of ARPES into a microscopic tool, permitting the electronic structure to be spatially mapped across the surface of a sample. This comes at the expense of a time-consuming scanning process to cover not only a three-dimensional energy-momentum (E, kx, ky) space but also the two-dimensional surface area. Here, we implement a protocol to autonomously search both k- and real-space in order to find positions of particular interest, either because of their high photoemission intensity or because of sharp spectral features. The search is based on the use of Gaussian process regression and can easily be expanded to include additional parameters or optimization criteria. This autonomous experimental control is implemented on the SGM4 micro-focus beamline of the synchrotron radiation source ASTRID2. [ABSTRACT FROM AUTHOR]

This article explores the use of synchrotron X-rays and Bragg Coherent Diffraction methods to image domain dynamics in crystalline solid state samples. It provides two examples: the imaging of antiferromagnetic spin-ordered phase domains in La2−xSrxNiO4 and the imaging of nanocrystalline BaTiO3 domains. The article explains the significance of coherent Bragg diffraction methods for imaging domains and describes the two methods used: Bragg Coherent Diffractive Imaging (BCDI) and Bragg Ptychography. It also discusses the challenges and techniques involved in imaging magnetic domain structures. The research was supported by the U.S. Department of Energy and the U.K. Engineering and Physical Sciences Research Council. [Extracted from the article]

The beam position is the most important reference basis for the operation of synchrotron radiation light sources, particularly for commissioning the first-turn injection of fourth-generation light sources. To improve the accuracy of the beam position measurement, we analyzed methods for calculating the beam position, and a finite element calculation and the stretched wire calibration system were used to demonstrate the procedure. We proved the relationship between the coverage range, fitting order, scanning step size, and accuracy both theoretically and experimentally, which can provide a basis for selecting the appropriate fitting order for different operation stages of the accelerator. It was proved that the accuracy of beam position calculations using simplified polynomial coefficients is comparable to those without a simplified one, which can save resources for reading electronic processing. The testing results of a batch of beam position monitors (BPMs) were in good agreement with the finite element calculation results, and the small difference between the manufactured BPMs also proved that quality control was performed well, and it benefited from button sorting. [ABSTRACT FROM AUTHOR]

The article announces new members of Chinese Academy of Sciences (Chemistry 2023) which includes Junbiao Chang, Chunying Chen, and Huisheng Peng.

Small-angle scattering (SAS) of X-rays and neutrons is a technique for studying the subatomic structure of condensed matter with a resolution of tenths to hundreds of nanometers, the capabilities of which have grown significantly in recent decades due to the emergence of bright synchrotron radiation sources and laboratory facilities with microfocus sources. The growth of computing power was accompanied by the development of new algorithms and techniques for data analysis, which made SAS one of the most effective methods for studying nanoscale structures. After a brief presentation of the basic principles of SAS for isotropic dispersed nanosystems, some of the most striking examples of such analysis are given: modeling the structure of biological macromolecules in solution, determining the size distributions of inhomogeneities in polydisperse systems, and studying multicomponent systems of nanoparticles of different nature. The SAS method does not require special sample preparation and allows studying objects under conditions close to natural ones, which is especially demanded in the development of nature-like technologies. [ABSTRACT FROM AUTHOR]

Benefiting from the development of high‐brilliance synchrotron radiation sources, microbeam X‐ray scattering has become a well established scattering‐based imaging technology. This article describes the newly constructed time‐resolved microbeam small‐angle X‐ray scattering (µSAXS) experimental station at the BL10U1 beamline at the Shanghai Synchrotron Radiation Facility. The µSAXS endstation provides SAXS/WAXS measurements with a 10 µm hard X‐ray beam and a flux of ∼1012 photons s−1. A multi‐axis sample stage, an on‐axis viewer and in situ experimental apparatus are incorporated to facilitate multi‐method scientific experiments in various material fields. As scientific examples, this article explores 1D tomography, 2D mapping and tomographic sectioning based on X‐ray scattering to investigate the micro–nanostructures of polymer fiber, spherulite and bamboo samples. [ABSTRACT FROM AUTHOR]

Fluorescence‐detected linear dichroism (FD‐LD) enables one to collect linear dichroism spectra for oriented fluorophores in the presence of other absorbing species and light scattering. The experiment proceeds by scanning the excitation wavelength and using a filter to collect only emitted photons from the fluorophore. Thus, it has the potential to give data with enhanced selectivity and quality. By using a synchrotron radiation light source and fluorescence‐detection, we show data for a range of fluorophores in different orienting environments. Film and flow‐oriented FD‐LD spectra were collected down to 170 nm. Even for flow‐oriented liposomes, we have data collected down to 210 nm. For strongly scattering samples, for example, liposomes, FD‐LD has the clear advantage that scattering is absent for the longer wavelength fluorescence photons. The collimated and smaller beam size of the synchrotron radiation also gives rise to sharper and more well‐defined features in the spectra. [ABSTRACT FROM AUTHOR]

A plane-symmetric optical system with a two-dimensional field light source, such as a soft X-ray and vacuum ultraviolet optical system, is widely used for synchrotron radiation source devices, microscopes and so on. Therefore, this paper studied third-order intrinsic aberration modification with second-order accuracy transfer of pupil coordinates and extrinsic aberration of these kinds of optical systems. First, we discuss the extrinsic aberration calculation method and derive the corresponding aberration expressions; in addition, we apply optical geometric relations and the polynomial fitting method to obtain a second-order accuracy transfer relationship expression of the pupil coordinates between adjacent optical surfaces and derived the modification calculation expressions of the intrinsic aberration caused by the above factor. Finally, the third-order intrinsic aberration modification with second-order accuracy transfer of pupil coordinates and extrinsic aberration expressions derived in this paper are applied to calculate ray spot diagrams of two soft X-ray and vacuum ultraviolet optical systems with meridional and sagittal field angle light sources, and these results are compared with those obtained from the ray-tracing software Shadow; this showed that the calculation accuracy of the aberration expressions is sufficient. [ABSTRACT FROM AUTHOR]

A new vacuum ultraviolet absorption (VUV) spectrum of azulene vapor has been obtained by using a synchrotron radiation source. The onset of the ultraviolet spectrum, previously reported by Sidman et al., has been analyzed in detail by Franck–Condon (FC) and Herzberg–Teller (HT) methods. The photoelectron spectral profile identifies the 3px-Rydberg state 00 band to be 131 cm−1 from the VUV maximum. Excited state energy levels were calculated by three independent methods: the wide scan VUV spectrum was correlated with symmetry adapted cluster configuration interaction calculations. The low energy portion of the spectrum was studied by both time dependent density functional theoretical methods (TDDFT) and multi-reference multi-root CI (MRD-CI). Equilibrium structures were determined for valence states at the TDDFT level. Rydberg states were determined by both TDDFT and MRD-CI. The FC + HT analyses were performed on the TDDFT wave-functions. The HT intensity profiles are generally low in intensity, relative to the FC ones; however, HT is dominant in the second singlet state (S2, 11A1). As a result, numerous non-symmetric modes, their overtones, and combination bands show considerable intensity in that band. Energies obtained from use of extremely diffuse s-, p-, d-, or f-character functions enabled realistic extrapolation to the IE1 for many Rydberg states (RS). The lowest RS (3b13s) based on IE2 lies at 4.804 eV with a quantum defect of 0.714. Differentiation between valence and RS is readily made using the second moments of the charge distribution. [ABSTRACT FROM AUTHOR]

Superconducting undulators (SCUs) can offer a much higher on-axis undulator field than state-of-the-art cryogenic permanent-magnet undulators with the same period and vacuum gap. The development of shorter-period and high-field SCUs would allow the free-electron laser and synchrotron radiation source community to reduce both the length of undulators and the dimensions of the accelerator. Magnetic measurements are essential for characterizing the magnetic field quality of undulators for operation in a modern light source. Hall probe scanning is so far the most mature technique for local field characterization of undulators. This article focuses on the systematic error caused by thermal contraction that influences Hall probe measurements carried out in a liquid helium cryostat. A novel procedure, based on the redundant measurement of the magnetic field using multiple Hall probes at known relative distance, is introduced for the correction of such systematic error. [ABSTRACT FROM AUTHOR]

A method to optimize the thermal deformation of an indirectly cryo-cooled silicon crystal monochromator exposed to intense X-rays at a low-emittance diffraction-limited synchrotron radiation source is presented. The thermalinduced slope error of the monochromator crystal has been studied as a function of heat transfer efficiency, crystal temperature distribution and beam footprint size. A partial cooling method is proposed, which flattens the crystal surface profile within the beam footprint by modifying the cooling contact area to optimize the crystal peak temperature. The optimal temperature varies with different photon energies, which is investigated, and a proper cooling strategy is obtained to fulfil the thermal distortion requirements over the entire photon energy range. At an absorbed power up to 300 W with a maximum power density of 44.8 W mm-2 normal incidence beam from an in-vacuum undulator, the crystal thermal distortion does not exceed 0.3 mrad at 8.33 keV. This method will provide references for the monochromator design on diffraction-limited synchrotron radiation or free-electron laser light sources. [ABSTRACT FROM AUTHOR]

The crystal structure of nilotinib hydrochloride monohydrate, being an active pharmaceutical substance of the drug Tasigna for chronic myeloid leukemia, is determined by powder X-ray diffraction (XRD) using a synchrotron radiation source of the National Research Center "Kurchatov Institute". The molecular conformation of the cation in the crystal differs from that in the initial nilotinib molecule and its solvates due to the rotation of substituents about single C–N, C–O, and C–C bonds. In the crystal, the nilotinib molecule is protonated at the nitrogen atom of the imidazolium heterocycle and involved in the N–H...N, N–H...O, and N–H...Cl hydrogen bonds with another cation, water molecule, and anion respectively. The resulting structure is determined with high accuracy. Errors in bond lengths are only slightly worse than those for the structures determined from single crystal XRD data. In addition, one of the best values of the half uncertainty window (HUW) is achieved in the refinement. The importance of this parameter is considered in the article. The structure agrees with the solid-state NMR data. The comparison of the results with the solution NMR spectroscopy data reveals noticeable changes in the nilotinib molecular structure during crystallization. [ABSTRACT FROM AUTHOR]

The latest synchrotron radiation sources have the capability to produce X-ray beams with a photon flux that can be up to three orders of magnitude higher than previous-generation facilities, and that are not manageable by the currently available 2D photon-counting pixel detectors. The construction of new detectors that exceed the limitations of existing devices is a critical strategic need. Developing such detectors is a challenge in terms of readout electronics as well as sensor material, particularly in the case of devices intended to operate at X-ray energies above 30 keV. The approach adopted at the ESRF to deal with this major difficulty is twofold: the use of a novel semiconductor material with improved electrical properties, high-flux CdZnTe, and the investigation of a specific readout scheme, incremental digital integration, via the XIDer project in collaboration with the University of Heidelberg. Incremental digital integration is a method intended to be less sensitive to variations of the dark current than the conventional charge integration readout. However, this readout scheme requires that the leakage current from the sensor material stays below a certain threshold to reduce the leakage contributions. This paper introduces the ESRF strategy and few examples of the methods employed to evaluate the performance and leakage current behavior of high-flux CdZnTe pixelated sensors. These examples illustrate the first results obtained with this material under moderate to very high X-ray irradiation fluxes of up to 1012 photons/mm²/s. [ABSTRACT FROM AUTHOR]

A high-resolution monochromator with a broad spectral range of 125–4200 Å is designed for a measuring beamline of the projected synchrotron radiation source "SKIF" (Novosibirsk). The optical configuration of the monochromator comprises a grazing-incidence concave mirror, a plane VLS grating, and an exit slit. It is planned to use two replaceable VLS gratings with central groove frequencies of 600 and 150 mm–1 intended for subranges of 125–1000 Å and 900–4200 Å, respectively. Wavelength tuning in each of the two subranges is carried out by solely the rotation of the VLS-gratings. Due to the proper choice of p1 VLS-grating coefficients, the focal distance varies only slightly over the entire spectral range, and the p2 VLS-grating coefficients are used to suppress the aberrations of the mirror and the gratings. The resolving power of the configuration obtained by numerical ray tracing exceeds 1000 in the 125–1000 Å range and 2000 in the 900–4200 Å range. [ABSTRACT FROM AUTHOR]

Gas bremsstrahlung, generated by the interaction between stored electrons and residual gas in electron storage rings, is an important radiation source for the shielding of synchrotron radiation (SR) facilities. In recent SR facilities, hydrogen was found dominant in the residual gas of the vacuum chambers of the electron storage rings, although air has been conventionally assumed as the bremsstrahlung target for the shielding designs of SR beamlines extended from the electron storage ring. To study the effect of residual gas composition on the dose rate outside shields, we calculated the intensity of gas bremsstrahlung based on the gas composition for both the air and the residual gas expected in the recent electron storage rings using an analytical formula and general-purpose Monte Carlo codes for particle transport calculations. The analytical shielding calculation with a realistic gas composition was found to well reproduce the energy spectra of gas bremsstrahlung simulated by the Monte Carlo codes. The correction factors between the air and the realistic gas compositions are applied to the conventional analytical formulas for dose estimation of secondary radiations generated by the interaction between the bremsstrahlung from air and beamline components. [ABSTRACT FROM AUTHOR]

Wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy is a widely used instrumental spectroscopy method for a variety of samples and it requires no or a minimal of sample preparation. Compared to using the more conventional energy dispersive XRF spectrometers, WD-XRF spectroscopy has the advantage of a highly improved energy resolution, making this technique suitable for the detection of characteristic X-rays separated by only a few eV. WD-XRF is established both in industry for routine analyses and in the academic world for high-end research and development of the method. WD-XRF spectroscopy can be probed with a laboratory X-ray source and if higher X-ray-beam intensities, monochromatic and polarized beams are required a synchrotron X-ray radiation source can be used. In (synchrotron) radiation facilities all over the world interesting new setups are characterized and used. This review paper will give an overview of the important characteristic properties, such as energy resolution, sensitivity, and the reachable energy range of the different types of WD-XRF setups available and reported in the last 20 years, based on laboratory X-ray sources, radiation facility sources or availability as a commercial instrument. The commercially available instruments are listed by the manufacturer and type of instrument, and for each instrument at least one example of an application is shown. [ABSTRACT FROM AUTHOR]

In this work, the chaotic motions of relativistic electrons in X-ray free-electron lasers are investigated using an optical undulator in the presence of a magnetized ion-channel background. To miniaturize X-ray light sources, the optical undulator is a promising concept. The optical undulator provides higher optical gain than conventional magnetostatic undulators due to its micrometer wavelength. In addition, it reduces the required electron beam energy from several GeV to the multi-MeV range to produce X-ray pulses. The interaction of an optical undulator with an intense relativistic electron beam is a highly non-linear phenomenon that can lead to chaotic dynamics. At synchrotron radiation sources, the possibility of chaos control for X-ray FELs can be critical for certain classes of experimental studies. The equations of motion for a relativistic electron propagating through the optical undulator in the presence of a magnetized ion-channel can be derived from the Hamiltonian of the interaction region. Simulation results revealed that the intensity of the perturbation route from orderly behavior to chaos depends on the beam density, axial magnetic field strength, ion-channel density parameter, and pump laser undulator. Specific values of parameters were obtained for the transition from regular to chaotic paths. Bifurcation diagrams of the system were plotted to demonstrate the origin of chaos at a critical point, and Poincaré maps were created to distinguish between chaotic and orderly motions of electrons. The proposed new scheme can help to improve X-ray FELs, which have potential usages in basic sciences, medicine, and industry. [ABSTRACT FROM AUTHOR]

Clinopyroxene is a major rock forming mineral capable of incorporating diverse metal cations. As a consequence, clinopyroxene preserves valuable archives of magmatic processes. Understanding clinopyroxene is thus essential for understanding Earth's wider chemical evolution. However, knowledge about the relative abundances of ferrous and ferric iron in magmatic clinopyroxene remains sparse because it is not currently possible to routinely measure the valence of iron in clinopyroxene crystals without either separating single crystals for bulk analysis or securing access to Mössbauer spectroscopy or a synchrotron radiation source to perform in-situ microanalysis. This is despite magmatic clinopyroxene crystals often containing appreciable quantities of ferric iron that affect its stability and behaviour in currently ill-constrained ways and limit our ability to exploit its chemistry to robustly reconstruct conditions of magma storage and evolution. Here we integrate optimised electron probe microanalysis and Mössbauer spectroscopy on endmember and single-crystal clinopyroxene samples to re-evaluate previously discredited approaches for estimating clinopyroxene ferric iron contents by stoichiometry. By ensuring that we measured all major and minor elements in clinopyroxene crystals with sufficient precision, we show that it is possible to readily obtain stoichiometric estimates of clinopyroxene ferric-to-total iron ratios with similar precisions to those derived from Mössbauer spectroscopy (1 σ ∼ 3.5% absolute). Being able to robustly determine clinopyroxene ferric iron contents enables us to propose a new empirical scheme for assigning clinopyroxene components that explicitly accounts for ferric iron, which is primarily hosted within esseneite component (CaFe 3 + AlSiO 6 ) in clinopyroxenes dominated by quadrilateral components and aegirine component (NaFe 3 + Si 2 O 6 ) in alkali clinopyroxenes. Our new scheme provides a framework for documenting the full spectrum of clinopyroxene compositions in both natural and experimental systems when analyses are performed with sufficient precision. [ABSTRACT FROM AUTHOR]

The lattice of the fourth-generation of the SYLA electron storage synchrotron of 6 GeV is scaled using the resources of the National Research Center Kurchatov Institute. Parameters of the storage synchrotron that provide design parameters of electron beams in the accumulator have been calculated. The dynamic aperture, momentum acceptance, and Touschek lifetime of the beams were determined, both in the case of no errors in the adjustment of magnetic structure elements and field values in a closed orbit and in their presence, taking into account losses due to synchrotron radiation and quantum excitation. Kicker magnets have been adapted to provide efficient off-axis injection. [ABSTRACT FROM AUTHOR]

Crystals of the enzyme purine nucleoside phosphorylase from the extremophilic bacterium Halomonas Chromatireducens AGD 8-3, suitable for X-ray diffraction, were grown by the vapor-diffusion method. The X-ray diffraction data were collected from these crystals at the Belok beamline of the Kurchatov synchrotron radiation source (National Research Centre "Kurchatov Institute") at 100 K to 1.80 Å resolution. The X-ray diffraction data were processed in the space groups P1, P2, P21, and P622. The structure was solved by the molecular replacement method taking into account the twinning in the space groups P21 and P1 with one and two hexamers of the enzyme per asymmetric unit, respectively. [ABSTRACT FROM AUTHOR]

Coronavirus SARS-CoV-2 was the cause of global pandemic COVID-19 that has claimed millions of lives around the world. One of the approaches to the therapy of severe forms of COVID-19 is based on the use of virus-neutralizing antibodies against the receptor-binding domain (RBD) of the virus spike glycoprotein (S). Detailed structural data on particular epitopes recognized by these virus-neutralizing antibodies is an important aspect of the improvement of available antibodies in order to extend the range of recognized virus strains. A stoichiometric complex of the virus-neutralizing single-domain antibody P2C5 and the glycosylated form of SARS-CoV-2 S protein RBD was obtained. Despite numerous conditions in which the crystal growth of the complex was observed, these crystals showed poor diffraction, apparently because of heterogeneity associated with the glycosylation of RBD. With the aim of improving the crystal quality, deglycosylase PNGase F was produced in a bacterial expression system and deglycosylation of RBD was performed. Despite low solubility of the deglycosylated form of RBD, it retains the ability to bind to the nanoantibody P2C5, resulting in the formation of a stable heterodimeric complex during gel filtration. The crystals of this complex were obtained. They showed diffraction to a similar resolution of ~4 Å on a laboratory X-ray diffractometer and at a synchrotron radiation source. The symmetry space group, the unit cell parameters of the crystal, and its protein composition were determined. [ABSTRACT FROM AUTHOR]

The utilization of a low-frequency (<200 MHz) RF system in storage facilitates the attainment of ultra-low emittances in synchrotron light sources through on-axis injection. This paper focuses on the development of a low-frequency normal conducting (NC) cavity with higher-order mode (HOM) damping for fourth-generation synchrotron light sources. We propose a novel approach to achieve efficient HOM damping in a NC cavity by optimizing the lowest frequency HOM and implementing a beam-line absorber. Notably, unlike conventional NC cavities, the presence of a large beam tube for the beam-line absorber does not compromise the accelerating performance in a coaxial resonant cavity, enabling effective HOM damping while maintaining a high shunt impedance. Through simulations, the prototype design of a 166.6 MHz HOM-damped cavity demonstrates a fundamental mode impedance of ∼8 MΩ, with longitudinal and transverse HOM impedances below 2.0 and 50 kΩ/m, respectively. [ABSTRACT FROM AUTHOR]

Advances in research of magnetic two-dimensional van der Waals (2D vdW) materials have opened up new opportunities in miniaturization of spintronic devices at the atomically thin limit. One major research thrust, which is the subject of this review, is that the magnetism of 2D vdW materials and their derived hetero-interface may be significantly affected by the local atomic geometry and environment. As a result, there is a pressing need for powerful advanced technique to characterize magnetic vdW surface and interface. Circularly polarized X-rays from synchrotron radiation light sources are key to this endeavor, as they can probe the microscopic magnetism of a specific element, for their atomic sensitivity, element-specificity, core-level excitation as well as capability of separation for the spin and orbit moments. We review a series of representative experimental achievements, exploiting circularly polarized X-rays, in (1) 2D vdW magnet, (2) magnetic metal/vdW interface, (3) molecule/vdW interface as well as (4) vdW/2D interface. On the basis of the review, advantages of probing magnetic vdW surface and interface by circularly polarized X-rays are presented, and challenges and opportunities are also discussed. [ABSTRACT FROM AUTHOR]

The olivine-wadsleyite transformation is believed to occur at depths of about 410 km in the Earth, producing a major seismic discontinuity in this region of the Earth's mantle. The mechanism of this phase transition controls the microstructures of the newly nucleated wadsleyite, the major phase of the upper part of the mantle transition zone, and thus impacts seismic observations in the region. Here, we study the microstructures produced by the olivine-wadsleyite transformation using in situ laboratory experiments at pressures and temperatures relevant for the mantle transition zone. We transform pure olivine samples in laser-heated diamond-anvil cells at pressures ranging from 12.3 to 20.2 GPa and temperatures of 1400–1730 K. At different steps of the transformation we measure the orientation and size distribution of individual sample grains using multigrain crystallography at synchrotron radiation sources. We find that the olivine to wadsleyite transformation is incoherent at the conditions of the mantle transition zone, and is probably dominated by nucleation of wadsleyite at grain boundaries of the parent olivine. Thus, we expect that seismic anisotropy near 410 km would drop significantly due to the randomized lattice preferred orientation of newly nucleated wadsleyite induced by the incoherent transformation. [ABSTRACT FROM AUTHOR]

The advent of next-generation synchrotron radiation sources and X-ray freeelectron lasers calls for high-quality Bragg-diffraction crystal optics to preserve the X-ray beam coherence and wavefront. This requirement brings new challenges in characterizing crystals in Bragg diffraction in terms of Bragg-plane height errors and wavefront phase distortions. Here, a quantitative methodology to characterize crystal optics using a state-of-the-art at-wavelength wavefront sensing technique and statistical analysis is proposed. The method was tested at the 1-BM-B optics testing beamline at the Advanced Photon Source for measuring silicon and diamond crystals in a self-referencing single-crystal mode and an absolute double-crystal mode. The phase error sensitivity of the technique is demonstrated to be at the λ/100 level required by most applications, such as the characterization of diamond crystals for cavity-based X-ray freeelectron lasers. [ABSTRACT FROM AUTHOR]

Photoemission spectroscopy, an experimental method based on the photoelectric effect, is now an indispensable technique used in various fields such as materials science, life science, medicine and nanotechnology. However, part of the experimental process of photoemission spectroscopy relies on experience and intuition, which is obviously a problem for novice users. In particular, photoemission spectroscopy experiments using high-brilliance synchrotron radiation as a light source are not easy for novice users because measurements must be performed quickly and accurately as scheduled within a limited experimental period. In addition, research on the application of information science methods to quantum data measurement, such as photoemission spectroscopy, is mainly aimed at the development of analysis methods, and few attempts have been made to clarify the problems faced by users who lack experience. In this study, the problems faced by novice users of photoemission spectroscopy are identified, and a native application named synapse with functions to solve these problems is implemented and evaluated qualitatively and quantitatively. This paper describes the contents of an interview survey, the functional design and the implementation of the application synapse based on the interview survey, and results and discussion of the evaluation experiment. [ABSTRACT FROM AUTHOR]

Absolute grand total cross section for electron scattering from CO 2 is obtained in the energy range from 20 eV down to 9 meV with a very narrow electron energy width of 11 meV using the threshold-photoelectron source employing synchrotron radiation. Although the obtained grand total cross section shows the general features of the cross-section behavior known for the low-energy electron scattering from CO 2 , namely the marked rise below 2 eV and the resonance enhancement at about 4 eV, several new features were revealed, especially at the 2 Π u resonance. The energy position for the maxima of the grand total cross section at the 2 Π u resonance appeared to be lower than that has been known. Also found are clear oscillatory structures resolved on the broad enhancement of the grand total cross section at around the 2 Π u resonance. The present measurement also revealed a threshold feature due to the vibrational excitation of asymmetric stretch mode in the grand total cross section. The vibrational excitation cross section for asymmetric stretch mode at the threshold is estimated from the feature. [ABSTRACT FROM AUTHOR]

We have studied the laser induced ultrafast quenching of Gd 4f magnetic order in ferrimagnetic Co100-xGdx alloys to highlight the role of the Co 3d–Gd 5d inter-atomic exchange coupling. We have taken advantage of the ultrashort soft X-ray pulses deliver by the femtoslicing beamline at the BESSY II synchrotron radiation source at the Helmholtz–Zentrum Berlin to perform element- and time-resolved X-ray Magnetic Circular Dichroism spectroscopy. Our results show that the laser induced quenching of Gd 4f magnetic order occurs on very different time-scales for the Co72Gd28, the Co77Gd23 and the Co79Gd21 alloys. Most of the magnetic moment losses occur within the first picosecond (ps) while the electron distribution is strongly out of equilibrium. After the equilibration of the electrons and lattice temperatures (t > 1 ps), the magnetic losses occur on slower rates that depend on the alloy composition: increasing the Co composition speeds up the demagnetization of Gd 4f sublattice. The strength of the Co 3d–Gd 5d inter-atomic exchange coupling which depends on composition, determines the efficiency of the angular momentum flow from the Gd 4f spin towards the lattice. Our results are in qualitative agreements with the predictions of the microscopic three temperatures model for ferrimagnetic alloys. [ABSTRACT FROM AUTHOR]

Ptychographic coherent diffraction imaging (PCDI) is a synchrotron X-ray microscopy technique that provides high spatial resolution and a wide field of view. To improve the performance of PCDI, the performance of the synchrotron radiation source and imaging detector should be improved. In this study, ptychographic diffraction pattern measurements using the CITIUS high-speed X-ray image detector and the corresponding image reconstruction are reported. X-rays with an energy of 6.5 keV were focused by total reflection focusing mirrors, and a flux of ~2.6 × 1010 photons s-1 was obtained at the sample plane. Diffraction intensity data were collected at up to ~250 Mcounts s-1 pixel-1 without saturation of the detector. Measurements of tantalum test charts and silica particles and the reconstruction of phase images were performed. A resolution of ~10 nm and a phase sensitivity of ~0.01 rad were obtained. The CITIUS detector can be applied to the PCDI observation of various samples using low-emittance synchrotron radiation sources and to the stability evaluation of light sources. [ABSTRACT FROM AUTHOR]

Vertical beam size measurements were carried out at Beijing Electron-Positron Collider II (BEPCII) using a phase grating and an absorption grating based on the Talbot effect. The transverse coherence of synchrotron radiation is closely related to beam size. Due to the partial coherence of the synchrotron radiation source, the coherence length can be calculated by measuring the visibility decay of interferograms recorded at different distances behind the gratings. A vertical beam size of 68.19 ± 2 mm was obtained based on the relationship between the coherence length and beam size at the 3W1 beamline of BEPCII. A comparison of the vertical emittance derived from the grating Talbot method and the synchrotron radiation visible light interferometer method was presented. The vertical emittances from the two methods are 1.41 nm rad and 1.40 nm rad, respectively. The 0.1% difference indicates that the grating Talbot method for beam size measurement is reliable. This technique has great potential for small beam size measurement of fourth-generation synchrotron radiation light sources, considering its small diffraction limitation and simple experimental setups. [ABSTRACT FROM AUTHOR]

To evaluate the lattice misorientation at domain boundaries (DBs) in β‐Ga2O3, we performed X‐ray diffraction imaging (XRDI), X‐ray reticulography (XRR), and X‐ray topography (XRT) using a synchrotron radiation light source. Four reciprocal lattice vectors (g‐vectors) were applied, and the DBs showed different visibilities in the XRDI maps depending on the g‐vector. By analyzing possible characteristics of the misorientation, the XRDI results suggested that the DB being investigated was associated with a misorientation on the (10¯05$\overline {10} 05$) plane and contained twist and tilt components. The apparent peak change in XRDI caused by the two components was calculated. We further succeeded in separating the tilt and twist components using XRR images in conjunction with simulation. Dislocation arrays at the DBs were observed using XRT, and the average distance between the dislocations in the array was consistent with the misorientation obtained using XRDI and XRR. The distribution of DBs across a wide area was acquired by a combination of XRR images recorded on a charge‐coupled device camera and X‐ray films. The fringe‐patterned XRR on X‐ray films provided a powerful and nondestructive tool to characterize DBs distributed across a large‐diameter wafer with an angular resolution on the order of several arc sec (low 10−5 rad). [ABSTRACT FROM AUTHOR]

Synchrotron radiation light source has brought about new discoveries in a wide range from basic scientific research, technical innovation to industry fields, which is offering extreme experimental means and conditions as a kind of typically large scientific user facility, like a giant microscope. Meanwhile, several major challenges, such as high technical complexity, long construction period and cost risk, request more caution of management practices. Monitoring and evaluating the scientific and technological performance are effective solutions to optimize the operation and use of synchrotron radiation light source. This paper assessed the scientific and technological performance and impact of Advanced Photon Source (APS) in USA as an example, especially from the perspective of 68 simultaneously beamlines/endstations, which are the key components of research infrastructure and the frontier of scientific service. The main dataset was constructed based on the academic paper records allocated from the official website, including the output using APS and by the staffs of APS focusing on the establishment, development and upgrade of APS during 1985 to 2019. Each beamline was analyzed under the framework of "facilitymetrics", and the quantitative performance measures included overall trend and activity level, discipline distribution, requirements in various countries, academic impact, hot themes and main experimental approaches. Furthermore, several issues about the sustainability of large facility were discussed briefly: (1) the necessary of upgrade; (2) the challenge and alternativity from new disruptive experimental instruments and technology; (3) supporting trans-disciplines scientific research effectively; (4) international cooperation and different access demands in various countries user. [ABSTRACT FROM AUTHOR]

Recently, fourth‐generation synchrotron sources with several orders of magnitude higher brightness and higher degree of coherence compared with third‐generation sources have come into operation. These new X‐ray sources offer exciting opportunities for the investigation of soft matter and biological specimens by small‐angle X‐ray scattering (SAXS) and related scattering methods. The improved beam properties together with the advanced pixel array detectors readily enhance the angular resolution of SAXS and ultra‐small‐angle X‐ray scattering in the pinhole collimation. The high degree of coherence is a major boost for the X‐ray photon correlation spectroscopy (XPCS) technique, enabling the equilibrium dynamics to be probed over broader time and length scales. This article presents some representative examples illustrating the performance of SAXS and XPCS with the Extremely Brilliant Source at the European Synchrotron Radiation Facility. The rapid onset of radiation damage is a significant challenge with the vast majority of samples, and appropriate protocols need to be adopted for circumventing this problem. [ABSTRACT FROM AUTHOR]

This study employed a vacuum ultraviolet synchrotron radiation source and reflectron time‐of‐flight mass spectrometry (TOF‐MS) to investigate the photoionization and dissociation of styrene. By analyzing the photoionization mass spectrum and efficiency curve alongside G3B3 theoretical calculations, we determined the ionization energy of the molecular ion, appearance energy of fragment ions, and relevant dissociation pathways. The major ion peaks observed in the photoionization mass spectra of styrene correspond to C8H8+, C8H7+ and C6H6+. The ionization energy of styrene is measured as 8.46 ± 0.03 eV, whereas the appearance energies of C8H7+ and C6H6+ are found to be 12.42 ± 0.03 and 12.22 ± 0.03 eV, respectively, in agreement with theoretical values. The main channel for the photodissociation of styrene molecular ions is the formation of benzene ions, whereas the dissociation channel that loses hydrogen atoms is the secondary channel. Based on the experimental results and empirical formulas, the required dissociation energies (Ed) of C8H7+, C8H6+ and C6H6+ are calculated to be (3.96 ± 0.06), (4.00 ± 0.06) and (3.76 ± 0.06) eV, respectively. Combined with related thermochemical parameters, the standard enthalpies of formations of C8H8+, C8H7+, C8H6+ and C6H6+ are determined to be 964.2, 1346.3, 1350.2 and 1327.0 kJ/mol, respectively. Based on the theoretical study, the kinetic factors controlling the styrene dissociation reaction process are determined by using the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. This provides a reference for further research on the atmospheric photooxidation reaction mechanism of styrene in atmospheric and interstellar environments. [ABSTRACT FROM AUTHOR]

Achieving optimal design and precise control of the internal structure of laser-target materials are the primary objectives in various laser physics experiments, particularly in generating high flux photon and neutron beams. The study of low-density materials poses considerable challenges for X-ray analysis due to their high transparency and minimal contrast. In this study, to obtain clear visualization of foams with sparse structures, we used phase-contrast X-ray tomography, utilizing a high-quality monochromatic X-ray beam from the synchrotron radiation source PETRA-III at DESY. Employing phase-contrast algorithms, the 3D structure of a foam-suspended glass microsphere inside the plastic cylinder was reconstructed with a level of image quality sufficient to visualize uniformity, displacement, and surface roughness on both sides of the microsphere. The primary focus of this investigation was a CH plastic capillary including 10 mg/cc CHO foam with a glass microsphere positioned at the center. The results of this study demonstrate that phase-contrast X-ray tomography with coherent synchrotron radiation is an effective and valuable technique for the development of new laser targets containing structured low-density materials. [ABSTRACT FROM AUTHOR]

Mid-infrared microspectroscopy is a non-invasive tool for identifying the molecular structure and chemical composition at the scale of the probe, i.e. at the scale of the beam. Consequently, investigating small objects or domains (commensurable to the wavelength) requires high-resolution measurements, even down to the diffraction limit. Herein, different protocols and machines allowing high-resolution measurements in transmission mode (aperture size (i.e., beam size) from 15 × 15 μm to 3 × 3 μm) are tested using the same sample. The model sample is a closed cavity containing a water–air assemblage buried in a quartz fragment (fluid inclusion). The spectral range covers the water stretching band (3000–3800 cm−1), whose variations are followed as a function of the distance to the cavity wall. The experiments compare the performance of one focal plane array (FPA) detector associated with a Globar source with respect to a single-element mercury cadmium telluride (MCT) detector associated with a supercontinuum laser (SCL) or a synchrotron radiation source (SRS). This work also outlines the importance of post-experimental data processing, including interference fringe removal and Mie scattering correction, to ensure that the observed spectral signatures are not related to optical aberrations. We show that the SCL and the SRS-based setups detect specific spectral features along the quartz boundary (solid surface), invisible to the FPA imaging microscope. Additionally, the broadband SCL thus has the potential to substitute at the laboratory scale the SRS for conducting diffraction-limited high-resolution measurements. [ABSTRACT FROM AUTHOR]

We present a concept design of the CCU SKIF–NSU Experimental Station 1-7 "Basic methods of synchrotron diagnostics for educational, research, and innovative activities of students" for improving the efficiency of the educational process and helping the NSU students to solve research problems using the capabilities of a modern synchrotron radiation source. Several research methods are planned to be jointly implemented at the Experimental Station 1-7: powder and single-crystal X-ray diffraction, X-ray absorption spectroscopy, and X-ray fluorescence analysis. This research complex will not only allow solving a wide range of scientific problems in various fields of science such as physics, biology, chemistry, geology, archeology and medicine, but will also become an essential element of the practical education of scientific and technical stuff for the synchrotron research. [ABSTRACT FROM AUTHOR]

Synchrotron radiation microcomputed tomography (SR‐μCT) can provide non‐destructive three‐dimensional investigation for soft tissue with high resolution. The aim of this study is to evaluate technical improvements in microcomputed tomographic imaging of human lung tissue using a synchrotron radiation source at the 6C biomedical beamline. SR‐μCT images of excised human lung tissue (6 mm vertically and 10 mm horizontally sized) were explored at the 6C biomedical beamline in the Pohang accelerator laboratory (Pohang, Republic of Korea) using phase retrieval methods with a modified Bronnikov algorithm. Experimental data collection was performed with changes in the following conditions: the presence of a graphite attenuator, sample to detector distance, the presence of different scintillators and increasing pixel sizes. We identified that the resolution of lung tissue images was sufficiently enhanced when the graphite attenuator was not applied, 550 mm of sample to detector distance, with Cadmium tungsten (CdWO4) scintillator and twice binning of the pixel data and could be comparable with images from pathologic examination. Refinement of SR‐μCT techniques for soft tissue originating from the human body would advance the potential clinical application of synchrotron radiation in the near future. [ABSTRACT FROM AUTHOR]

The progress of miniaturization in integrated electronics has led to atomic and nanometer‐sized dopant devices in silicon. Such structures can be fabricated routinely by hydrogen resist lithography, using various dopants such as P and As. However, the ability to non‐destructively obtain atomic‐species‐specific images of the final structure, which would be an indispensable tool for building more complex nano‐scale devices, such as quantum co‐processors, remains an unresolved challenge. Here, X‐ray fluorescence is exploited to create an element‐specific image of As dopants in Si, with dopant densities in absolute units and a resolution limited by the beam focal size (here ≈1 µm), without affecting the device's low temperature electronic properties. The As densities provided by the X‐ray data are compared to those derived from Hall effect measurements as well as the standard non‐repeatable, scanning tunneling microscopy and secondary ion mass spectroscopy, techniques. Before and after the X‐ray experiments, we also measured the magneto‐conductance, which is dominated by weak localization, a quantum interference effect extremely sensitive to sample dimensions and disorder. Notwithstanding the 1.5 × 1010 Sv (1.5 × 1016 Rad cm−2) exposure of the device to X‐rays, all transport data are unchanged to within experimental errors, corresponding to upper bounds of 0.2 Angstroms for the radiation‐induced motion of the typical As atom and 3% for the loss of activated, carrier‐contributing dopants. With next generation synchrotron radiation sources and more advanced optics, the authors foresee that it will be possible to obtain X‐ray images of single dopant atoms within resolved radii of 5 nm. [ABSTRACT FROM AUTHOR]

Synchrotron radiation sources are widely used in interdisciplinary research, generating an enormous amount of data while posing serious challenges to the storage, processing, and analysis capabilities of the large-scale scientific facilities worldwide. A flexible and scalable computing architecture, suitable for complex application scenarios, combined with efficient and intelligent scheduling strategies, plays a key role in addressing these issues. In this work, we present a novel cloud–edge hybrid intelligent system (CEHIS), which was architected, developed, and deployed by the Big Data Science Center (BDSC) at the Shanghai Synchrotron Radiation Facility (SSRF) and meets the computational needs of the large-scale scientific facilities. Our methodical simulations demonstrate that the CEHIS is more efficient and performs better than the cloud-based model. Here, we have applied a deep reinforcement learning approach to the task scheduling system, finding that it effectively reduces the total time required for the task completion. Our findings prove that the cloud–edge hybrid intelligent architectures are a viable solution to address the requirements and conditions of the modern synchrotron radiation facilities, further enhancing their data processing and analysis capabilities. [ABSTRACT FROM AUTHOR]