Bending Magnet Beamline Research Articles

GIWAXS experimental methods at the NFPS-BL17B beamline at Shanghai Synchrotron Radiation Facility.

The BL17B beamline at the Shanghai Synchrotron Radiation Facility was first designed as a versatile high-throughput protein crystallography beamline and one of five beamlines affiliated to the National Facility for Protein Science in Shanghai. It was officially opened to users in July 2015. As a bending magnet beamline, BL17B has the advantages of high photon flux, brightness, energy resolution and continuous adjustable energy between 5 and 23 keV. The experimental station excels in crystal screening and structure determination, providing cost-effective routine experimental services to numerous users. Given the interdisciplinary and green energy research demands, BL17B beamline has undergone optimization, expanded its range of experimental methods and enhanced sample environments for a more user-friendly testing mode. Thesemethods include single-crystal X-ray diffraction, powder crystal X-ray diffraction, wide-angle X-ray scattering, grazing-incidence wide-angle X-ray scattering (GIWAXS), and fully scattered atom pair distribution function analysis, covering structure detection from crystalline to amorphous states. This paper primarily presents the performance of the BL17B beamline and the application of the GIWAXS methodology at the beamline in the field of perovskite materials.

Monolayer calibration of endofullerenes with x-ray absorption from implanted keV ion doses

X-ray absorption spectroscopy (XAS) has the highest sensitivity for chemical element detection on surfaces. With this approach, small amounts of lanthanide-containing endofullerene molecules (Ho3N@C80) have been measured by total electron yield at a low flux bending magnet beamline. The monolayer coverage is calibrated by extrapolating the signals of constant doses (3×1014 cm−2) of Ho ions implanted into SiO2 with energies between 2 and 115 keV. At room temperature, the Ho XAS spectra of the molecules and implanted ions indicate trivalent but not identical Ho ground states. Still, this approach demonstrates a way for calibration of small coverages of molecules containing open core-shell elements.

An active piezoelectric plane X-ray focusing mirror with a linearly changing thickness.

X-ray mirrors for synchrotron radiation are often bent into a curved figure and work under grazing-incidence conditions due to the strong penetrating nature of X-rays to most materials. Mirrors of different cross sections have been recommended to reduce the mirror's slope inaccuracy and clamping difficulty in order to overcome mechanical tolerances. With the development of hard X-ray focusing, it is difficult to meet the needs of focusing mirrors with small slope error with the existing mirror processing technology. Deformable mirrors are adaptive optics that can produce a flexible surface figure. A method of using a deformable mirror as a phase compensator is described to enhance the focusing performance of an X-ray mirror. This paper presents an active piezoelectric plane X-ray focusing mirror with a linearly changing thickness that has the ability of phase compensation while focusing X-rays. Benefiting from its special structural design, the mirror can realize flexible focusing at different focusing geometries using a single input driving voltage. A prototype was used to measure its performance under one-dimension and two-dimension conditions. The results prove that, even at a bending magnet beamline, the mirror can easily achieve a single-micrometre focusing without a complicated bending mechanism or high-precision surface processing. It is hoped that this kind of deformable mirror will have a wide and flexible application in the synchrotron radiation field.

Full-field hard X-ray nano-tomography at SSRF.

An in-house designed transmission X-ray microscopy (TXM) instrument has been developed and commissioned at beamline BL18B of the Shanghai Synchrotron Radiation Facility (SSRF). BL18B is a hard (5-14 keV) X-ray bending-magnet beamline recently built with sub-20 nm spatial resolution in TXM. There are two kinds of resolution mode: one based on using a high-resolution-based scintillator-lens-coupled camera, and the other on using a medium-resolution-based X-ray sCMOS camera. Here, a demonstration of full-field hard X-ray nano-tomography for high-Z material samples (e.g. Au particles, battery particles) and low-Z material samples (e.g. SiO2 powders) is presented for both resolution modes. Sub-50 nm to 100 nm resolution in three dimensions (3D) has been achieved. These results represent the ability of 3D non-destructive characterization with nano-scale spatial resolution for scientific applications in many research fields.

PolyX beamline at SOLARIS—Concept and first white beam commissioning results

PolyX is a compact bending magnet beamline under construction at National Synchrotron Radiation Centre SOLARIS, which will be available to users in mid-2023. The beamline is focused on X-ray microimaging and microspectroscopy in the tender/hard (4–15 keV) X-ray energy range. The name PolyX comes from polycapillary X-ray optics that will be extensively used for efficient X-ray focusing and from the possibility of using polychromatic or broadband X-rays to increase the rather low flux from the SOLARIS bending magnet in the hard X-ray energy range. Polycapillary optics will provide focal spots with sizes of 8–200 μm. Single bounce ellipsoidal capillary is expected to provide a ∼2 μm focal spot size. The main experimental techniques at PolyX will be X-ray absorption and phase-contrast imaging and microtomography, micro-X-ray fluorescence imaging and micro-X-ray absorption spectroscopy. This paper presents the concept of PolyX beamline and preliminary “white” beam commissioning results.

Assessing the prospect of XAFS experiments of metalloproteins under in vivo conditions at Indus-2 synchrotron facility, India.

The feasibility of X-ray absorption fine-structure (XAFS) experiments of ultra-dilute metalloproteins under in vivo conditions (T = 300 K, pH = 7) at the BL-9 bending-magnet beamline (Indus-2) is reported, using as an example analogous synthetic Zn (0.1 mM) M1dr solution. The (Zn K-edge) XAFS of M1dr solution was measured with a four-element silicon drift detector. The first-shell fit was tested and found to be robust against statistical noise, generating reliable nearest-neighbor bond results. The results are found to be invariant between physiological and non-physiological conditions, which confirms the robust coordination chemistry of Zn with important biological implications. The scope of improving spectral quality for accommodation of higher-shell analysis is addressed.

X-ray scattering at beamline BL2 of DELTA: Studies of lysozyme-lysozyme interaction in heavy water and structure formation in 1-hexanol

The experimental station of the bending magnet beamline BL2 of the Dortmund Synchrotron Radiation Source DELTA has been reconstructed in order to enable small-angle X-ray scattering and wide-angle scattering studies with monochromatic beam. By using a multilayer monochromator with a bandwidth of 1.5%, it is possible to reach a photon energy of 12 keV at sufficiently high photon fluxes. The beamline layout is described and the experimental capabilities are discussed by giving two examples of typical experiments: (i) A dense lysozyme solution is studied using small-angle X-ray scattering in order to reveal to influence of pressure on the protein-protein interaction with heavy water as solvent. (ii) The dependency of the hydrogen-bond mediated structure formation on temperature and pressure is investigated in liquid 1-hexanol by wide-angle X-ray scattering.

A spatial beam property analyzer based on dispersive crystal diffraction for low-emittance X-ray light sources

The advent of low-emittance synchrotron X-ray sources and free-electron lasers urges the development of novel diagnostic techniques for measuring and monitoring the spatial source properties, especially the source sizes. This work introduces an X-ray beam property analyzer based on a multi-crystal diffraction geometry, including a crystal-based monochromator and a Laue crystal in a dispersive setting to the monochromator. By measuring the flat beam and the transmitted beam profiles, the system can provide a simultaneous high-sensitivity characterization of the source size, divergence, position, and angle in the diffraction plane of the multi-crystal system. Detailed theoretical modeling predicts the system’s feasibility as a versatile characterization tool for monitoring the X-ray source and beam properties. The experimental validation was conducted at a bending magnet beamline at the Swiss Light Source by varying the machine parameters. A measurement sensitivity of less than 10% of a source size of around 12 µm is demonstrated. The proposed system offers a compact setup with simple X-ray optics and can also be utilized for monitoring the electron source.

X-ray absorption measurements at a bending magnet beamline with an Everhart–Thornley detector: A monolayer of Ho3N@C80 on graphene

X-ray Absorption Spectroscopy (XAS) is used for measuring monolayer quantities of Ho3N@C80 endofullerene molecules on graphene at a low flux bending magnet beamline. The total electron yield is measured with an Everhart–Thornley detector. In comparison to sample current measurements with the same noise level, our approach reduces data acquisition time and radiation dose by a factor of 25. As the first application of this setup, we report temperature-dependent measurements of the Ho M45 edge with per mille accuracy. This documents the advantages and capabilities of an Everhart–Thornely detector for XAS measurements under low x-ray flux.

Double-multilayer monochromators for high-energy and large-field X-ray imaging applications with intense pink beams at SPring-8 BL20B2

In this study, double-multilayer monochromators that generate intense, high-energy, pink X-ray beams are designed, installed and evaluated at the SPring-8 medium-length (215 m) bending-magnet beamline BL20B2 for imaging applications. Two pairs of W/B4C multilayer mirrors are designed to utilize photon energies of 110 keV and 40 keV with bandwidths of 0.8% and 4.8%, respectively, which are more than 100 times larger when compared with the Si double-crystal monochromator (DCM) with a bandwidth of less than 0.01%. At an experimental hutch located 210 m away from the source, a large and uniform beam of size 14 mm (V) × 300 mm (H) [21 mm (V) × 300 mm (H)] was generated with a high flux density of 1.6 × 109 photons s-1 mm-2 (6.9 × 1010 photons s-1 mm-2) at 110 keV (40 keV), which marked a 300 (190) times increase in the photon flux when compared with a DCM with Si 511 (111) diffraction. The intense pink beams facilitate advanced X-ray imaging for large-sized objects such as fossils, rocks, organs and electronic devices with high speed and high spatial resolution.

Experimental comparison of three methods to measure electron source properties for synchrotron radiation

Measuring the electron source size is essential for determining the emittance of synchrotron radiation. Pinhole imaging is the most common technique which measures the source profile in all transverse directions. The grating interferometry technique measures the coherence function of the x-ray beam, which indirectly determines the source size. The newly developed phase-space beam position and size monitor (ps-BPM) system provide information on electron source properties: position, angle, size, and divergence. These three techniques were used to determine the source size at a bend magnet beamline at the Canadian Light Source. In this work, we compare experimental results from these measurements at the same time, which is used as a cross-calibration procedure for each method.

The hard x-ray nanotomography microscope at the advanced light source.

Beamline 11.3.1 at the Advanced Light Source is a tender/hard (6-17keV) x-ray bend magnet beamline recently re-purposed with a new full-field, nanoscale transmission x-ray microscope. The microscope is designed to image composite and porous materials possessing a submicrometer structure and compositional heterogeneity that determine materials' performance and geologic behavior. The theoretical and achieved resolutions are 55 and <100nm, respectively. The microscope is used in tandem with a <25nm eccentricity rotation stage for high-resolution volume imaging using nanoscale computed tomography. The system also features a novel bipolar illumination condenser for the illumination of an ∼100μm spot of interest on the sample, followed by a phase-type zone plate magnifying objective of ∼52 µm field of view and a phase detection ring. The zone plate serves as the system objective and magnifies the sample with projection onto an indirect x-ray detection system, consisting of a polished single crystal CsI(Tl) scintillator and a range of high-quality Plan Fluorite visible light objectives. The objectives project the final visible light image onto a water-cooled CMOS 2048 × 2048-pixel2 detector. Here, we will discuss the salient features of this instrument and describe early results from imaging the internal three-dimensional microstructure and nanostructure of target materials, including fiber-reinforced composites and geomaterials.

Simultaneous two-color X-ray absorption spectroscopy using Laue crystals at an inverse-compton scattering X-ray facility.

X-ray absorption spectroscopy (XAS) is an element-selective technique that provides electronic and structural information of materials and reveals the essential mechanisms of the reactions involved. However, the technique is typically conducted at synchrotrons and usually only probes one element at a time. In this paper, a simultaneous two-color XAS setup at a laboratory-scale synchrotron facility is proposed based on inverse Compton scattering (ICS) at the Munich Compact Light Source (MuCLS), which is based on inverse Compton scattering (ICS). The setup utilizes two silicon crystals in a Laue geometry. A proof-of-principle experiment is presented where both silver (Ag) and palladium (Pd) K-edge X-ray absorption near-edge structure spectra were simultaneously measured. The simplicity of the setup facilitates its migration to other ICS facilities or maybe to other X-ray sources (e.g. a bending-magnet beamline). Such a setup has the potential to study reaction mechanisms and synergistic effects of chemical systems containing multiple elements of interest, such as a bimetallic catalyst system.

Simulations of applications using diaboloid mirrors

The diaboloid is a reflecting surface that converts a spherical wave to a cylindrical wave. This complex surface may find application in new Advanced Light Source bending-magnet beamlines or in other beamlines that now use toroidal optics for astigmatic focusing. Here, the numerical implementation of diaboloid mirrors is described, and the benefit of this mirror in beamlines exploiting diffraction-limited storage rings is studied by ray tracing. The use of diaboloids becomes especially interesting for the new low-emittance storage rings because the reduction of aberration becomes essential for such small sources. The validity of the toroidal and other mirror surfaces approximating the diaboloid, and the effect of the mirror magnification, are discussed.

The structure of oxide glasses studied by high-energy x-ray diffraction

The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron sources has created new approaches to study quantitatively the structure of noncrystalline materials. Recently, this technique has been combined with neutron diffraction at pulsed source to provide more detailed and reliable structural information not previously available. This article reviews and summarises recent results obtained from the high energy x‑ray diffraction on several oxide glasses, SiO2, B2O3 and PbSiO3, using bending magnet beamlines at SPring‑8. In particular, it addresses the structural models of the oxide glasses obtained by the reverse Monte Carlo (RMC) modelling technique using both the high energy x‑ray and neutron diffraction data.

Operation of a bending magnet beamline in large energy bandwidth mode for non-resonant X-ray emission spectroscopy

Two new operation modes, “pink beam” excitation, which has the energy bandwidth defined by X-ray mirrors and filters, and “broadband beam”, where the energy bandwidth is defined by the reflection from a multilayer monochromator, were implemented at the SuperXAS beamline of the Swiss Light Source (SLS). These setups allow measuring non-resonance X-ray emission spectra (XES) with 2–3 orders of magnitude higher incident flux than non-resonant XES measurements with a monochromatic incident beam. For the broadband beam mode, a Mo/Si multilayer structure was designed, with which the energy can be tuned in the 5–17 keV range. The multilayer demonstrates a relatively large energy bandwidth of 4 ± 0.2% through the whole energy range and a reflectivity of 23–60%, which increases with energy. We show that by using pink beam mode one can investigate the electronic structure of photocatalytic intermediates through time-resolved core-to-core XES experiments of diluted samples with a concentration of the element of interest of ~1 mM. Broadband beam mode is optimal for valence-to-core XES experiments and allow to avoid the excitation of additional KLβ satellites that can complicate the interpretation of spectra.

Magnetic design of a new source for bending magnet beamlines at ultra-low emittance ILSF ring

The Iranian Light Source Facility (ILSF) is a 3-GeV third-generation synchrotron radiation laboratory in the basic design phase. The storage ring (SR) is based on a five-bend achromat (5BA) lattice, which provides ultra-low horizontal emittance of 0.27 nm rad. It is recommended to use short-length wigglers for hard x-ray generation because of the ILSF storage ring straight section limitations. This article describes the magnetic design and optimization of the three-pole wiggler and its beam dynamics effects on the SR lattice that have been investigated for the ILSF. The 3D modeling and flux calculations have been carried out by the Radia, SPECTRA and SRW Codes.

Accurate high-resolution single-crystal diffraction data from a Pilatus3 X CdTe detector.

Hybrid photon-counting detectors are widely established at third-generation synchrotron facilities and the specifications of the Pilatus3 X CdTe were quickly recognized as highly promising in charge-density investigations. This is mainly attributable to the detection efficiency in the high-energy X-ray regime, in combination with a dynamic range and noise level that should overcome the perpetual problem of detecting strong and weak data simultaneously. These benefits, however, come at the expense of a persistent problem for high diffracted beam flux, which is particularly problematic in single-crystal diffraction of materials with strong scattering power and sharp diffraction peaks. Here, an in-depth examination of data collected on an inorganic material, FeSb2, and an organic semiconductor, rubrene, revealed systematic differences in strong intensities for different incoming beam fluxes, and the implemented detector intensity corrections were found to be inadequate. Only significant beam attenuation for the collection of strong reflections was able to circumvent this systematic error. All data were collected on a bending-magnet beamline at a third-generation synchrotron radiation facility, so undulator and wiggler beamlines and fourth-generation synchrotrons will be even more prone to this error. On the other hand, the low background now allows for an accurate measurement of very weak intensities, and it is shown that it is possible to extract structure factors of exceptional quality using standard crystallographic software for data processing (SAINT-Plus, SADABS and SORTAV), although special attention has to be paid to the estimation of the background. This study resulted in electron-density models of substantially higher accuracy and precision compared with a previous investigation, thus for the first time fulfilling the promise of photon-counting detectors for very accurate structure factor measurements.

A feasibility investigation of speciation by Fe K-edge XANES using a laboratory X-ray absorption spectrometer

We demonstrate effective speciation of Fe in model compounds from analysis of the weak pre-edge features in Fe K-edge XANES spectra, with a commercially available laboratory X-ray spectrometer, using a spherically bent crystal analyser and a low power X-ray tube, in Rowland circle geometry. Direct comparison with XANES data acquired from a third generation synchrotron bending magnet beamline, using the same specimens, validated quantitative agreement in determination of the total integrated intensity and centroid position of the pre-edge feature, which are a probe of the electronic configuration and symmetry of the absorber atom, and hence oxidation state and co-ordination number. This work opens the door to rapid and routine speciation studies of Fe by laboratory XANES, even for materials with relatively dilute absorber concentration of only a few mol. %.

Application of a phase space beam position and size monitor for synchrotron radiation source characterization

A phase space beam position and size monitor (ps-BPM) system was introduced previously to measure the electron source vertical position and angular motion along with the vertical source size and angular size at a single location in a synchrotron bend magnet beam line. The system was validated experimentally at the Canadian Light Source and demonstrated by a simulation that it is suitable for low-emittance light sources. In this work, the potential practicality of the ps-BPM system is explored with real-case studies. By combining the analysis in the time and frequency domain, information on the beam motion and size can be extracted and identified from both the source and the beam-line optics. Applications of the ps-BPM system at the Canadian Light Source are demonstrated by studying beam vibrations and machine insertion device field changes. Results of these studies provide guidelines for implementing a dedicated ps-BPM system at existing and planned synchrotron facilites.