Third International Workshop on Improving Data Quality in XAFS Spectroscopy, Q2XAFS2017

Introductory overview to the special issue papers from the Q2XAFS2017 workshop.

Propagation of uncertainty in experiment: structures of Ni (II) coordination complexes

An approach to investigate XAS data without standard interpolation of experimental data and with minimal loss of information content has been developed. The additional physical insight accorded by the correct propagation of experimental uncertainty has been used to determine newly refined structures for the innermost co-ordination shell of Ni(II) coordination complexes.

A call for a round robin study of XAFS stability and platform dependence at synchrotron beamlines on well defined samples

A program and methodology are proposed to study X-ray absorption fine structure of potential reference samples across XAS beamlines and synchrotron facilities, to enable each beamline to cross-calibrate, provide representative benchmarks and to enable more productive collaborative cross-facility activities.

A biological perspective towards a standard for information exchange and reporting in XAS

An X-ray absorption spectroscopy (XAS) data-reporting format is developed and its inclusion as standard supporting information in biological XAS publications is proposed. The aim of this text-based data-reporting XIF (XAFS information file) file format is to develop a consistent protocol for XAS data collection, analysis and interpretation, and, optionally, for sharing reference and reported data.

Steps towards XAFS beamline automation and remote access

Remote access to XAFS beamlines is an attractive option to reduce costs and provide an access route for educational and collaborative purposes. Any degree of automation of the operations, even if partial and limited to routine procedures, allows simplification of the remote user interface with significant improvement in the overall beamline efficiency. Here, some useful steps towards achieving this goal are introduced and the experience in this regard at the XAFS beamlines at LNLS and Diamond is described.

Fully automated beamline control system for XAS beamlines

State-of-the-art beamline automation for XAS beamlines implemented at the synchrotron at Karlsruhe Institute of Technology is described.

The challenge of constructing an international XAFS database

The present situation of the XAFS database in Japan and a proposal for the construction of an international collaboration XAFS database are presented.

Improving the quality of XAFS data

A summary of the discussion on aspects of a XAFS experiment that affect data quality, held at the Q2XAFS Workshop Satellite to IUCr Congress 2017 on `Data Acquisition, Treatment, Storage – quality assurance in XAFS spectroscopy' is reported.

Using EXAFS data to improve atomistic structural models of glasses

A simple scheme for the coherent incorporation of extended X-ray absorption fine-structure (EXAFS) spectroscopy data into the atomistic structure refinement of diffraction data obtained from melt-quenched glasses is demonstrated. The method is shown to significantly improve the quality and consistency of the finally generated structural models.

Fluorescence-detected XAS with sub-second time resolution reveals new details about the redox activity of Pt/CeO₂ catalyst

A highly sensitive setup for measuring fluorescence-detected X-ray absorption spectroscopy with sub-second time resolution has been developed at the SuperXAS beamline at the Swiss Light Source. This opens new opportunities for understanding the dynamic structure of heterogeneous catalysts.

The Spectroscopy Village at Diamond Light Source

The current status and technical details of the four instruments dedicated to X-ray spectroscopy available at Diamond Light Source are presented.

Single-particle XFEL 3D reconstruction of ribosome-size particles based on Fourier slice matching: requirements to reach subnanometer resolution

Three-dimensional structure reconstructions of ribosome from simulated XFEL diffraction patterns using a slice-matching approach provide insights on how XFEL single-particle experimental conditions and the amount of data affect the resulting resolution.

High Bragg reflectivity of diamond crystals exposed to multi-kW mm⁻² X-ray beams

Ultrahigh-precision Bragg reflectivity studies of diamond single crystals exposed to X-ray beams of power densities corresponding to the X-ray Free Electron Laser Oscillator are presented.

Performance of quartz- and sapphire-based double-crystal high-resolution (∼10 meV) RIXS monochromators under varying power loads

Quartz- and sapphire-based high-resolution double-bounce monochromators for RIXS spectroscopy at the Ir L₃ absorption edge are tested. At room-temperature operation it is found that quartz is substantially distorted by even small amounts of incident power, making it unsuitable for this application, whereas sapphire and silicon are reasonably unaffected.

Characterization of the X-ray coherence properties of an undulator beamline at the Advanced Photon Source

Methods are described to measure divergence by imaging the apparent source size using either slits to form a pinhole camera or a compound refractive lens. The values of brightness and coherent flux obtained are compared with those calculated for the undulator source, to evaluate the effects of beamline optics.

More are better, but the details matter: combinations of multiple Fresnel zone plates for improved resolution and efficiency in X-ray microscopy

The properties of stacking multiple Fresnel zone plates together at intermediate distances are considered. One can enhance the nanofocusing efficiency, and other characteristics, by careful choice of design parameters.

An all-diamond X-ray position and flux monitor using nitrogen-incorporated ultra-nanocrystalline diamond contacts

Diamond X-ray detectors with N-UNCD contacts have been demonstrated for X-ray flux measurement and position calibration. The contacts have significant advantages over traditional metal contacts due to a lack of extra absorption edges, less absorption in the soft X-ray range, and similar material properties to the underlying detector material.

Large-area single-photon-counting CdTe detector for synchrotron radiation computed tomography: a dedicated pre-processing procedure

Large-area single-photon-counting CdTe detectors are attractive due to their high-efficiency, low-noise and spectral performances but they still present several non-optimal behaviours (e.g. charge trapping, inter-module gaps etc.). These issues are addressed in this article where a comprehensive step-by-step description of a pre-processing procedure is presented and tested in the framework of a synchrotron radiation low-dose tomographic application on breast specimens.

Dual-polarity pulse processing and analysis for charge-loss correction in cadmium–zinc–telluride pixel detectors

Charge losses at the inter-pixel gap are typical drawbacks in cadmium–zinc–telluride pixel detectors. New techniques, based on the time coincidence analysis of both the positive and negative pulses, were applied to correct the charge losses near the inter-pixel region.

Improving the detection efficiency and modulation transfer function of lens-coupled indirect X-ray imaging detectors based on point spread functions simulated according to lens performance parameters

A geometric optical imaging method was established to simulate the lens-coupled X-ray imaging detector's point spread functions in the focus process according to performance parameters. The calculated point spread function was applied in deconvolution to improve the quality of blurred images caused by the thickness of the scintillator when using a thicker scintillator to improve the detection efficiency.

Elemental fingerprinting of mineral species in iron-fortified milk: anomalous small-angle X-ray scattering and resonant soft X-ray scattering studies

The advantages, challenges and limitations of two complementary techniques – resonant soft X-ray scattering and anomalous small-angle X-ray scattering – are presented, using iron-fortified milk as an example.

Smaller capillaries improve the small-angle X-ray scattering signal and sample consumption for biomacromolecular solutions

Sample exposure cells of small-angle X-ray scattering instruments often utilize cylindrical capillaries where the diameter, or path length, is typically selected to balance between scattering and absorption. Here it is demonstrated that, for radiation-sensitive solution samples, using capillaries with a diameter smaller than the optimal path length in combination with continuous sample flow improves the quality of the scattering signal for a given quantity of material.

Enhanced insulating behavior in the Ir-vacant Sr₂Ir_1–xO₄ system dominated by the local structure distortion

X-ray absorption spectroscopy was applied to study the enhanced insulating behavior in the Ir-vacant Sr₂Ir_1–xO₄ system. Data pointed out that both the more distorted IrO₆ octahedra and decreased Ir—O1—Ir angle contribute to the increment of the band gap, and then result in the enhanced insulating state for Sr₂Ir_1–xO₄.

Rutile- and anatase-type temperature-dependent pre-edge peak intensities in K-edge XANES spectra for AO (A = Mn), A₂O₃ (A = Sc, Cr and Mn) and AO₂ (A = Ti and V)

Pre-edge peaks in 3d transition-metal element (Sc, Ti, V, Cr and Mn) K-edge XANES (X-ray absorption near-edge structure) spectra in AO₂ (A = Ti and V), A₂O₃ (A = Sc, Cr and Mn) and AO (A = Mn) were measured at various temperatures. The difference peak is obtained from the difference between the low- and high-temperature XANES spectra.

Distributed X-ray photon correlation spectroscopy data reduction using Hadoop MapReduce

MapReduce-based implementation of computing auto-correlations for X-ray photon correlation spectroscopy data at beamline 8-ID at the Advanced Photon Source are presented.

3D reconstruction of magnetization from dichroic soft X-ray transmission tomography

By using soft X-ray transmission microscopy with magnetic contrast (magnetic circular dichroism) it is possible to obtain valuable magnetic information from the studied systems. In this work, in a step further, a method to use magnetic soft X-ray transmission tomography as an ideal tool to reconstruct the three-dimensional magnetization configuration of arbitrary magnetic samples is presented.

Synchrotron inline phase contrast µCT enables detailed virtual histology of embedded soft-tissue samples with and without staining

Protocols for combined synchrotron micro-computed tomography based virtual histology and classical histology of soft-tissue samples are presented.

In situ coherent X-ray diffraction imaging of radiation-induced mass loss in metal–polymer composite spheres

Coherent X-ray imaging of radiation damage to metal-coated polymer microspheres is reported.

A compact and flexible induction furnace for in situ X-ray microradiograhy and computed microtomography at Elettra: design, characterization and first tests

An induction furnace for in situ high-resolution synchrotron and laboratory hard X-ray microradiography and computed microtomography developed at the Elettra synchrotron radiation facility is described.

X-ray phase-contrast imaging with engineered porous materials over 50 keV

Engineered porous materials are proposed as random absorption masks for X-ray phase-contrast imaging in high-energy regions (i.e. over 50 keV).

Characterization of a submicro-X-ray fluorescence setup on the B16 beamline at Diamond Light Source

The use of the X-ray fluorescence setup on the B16 beamline at the Diamond Light Source for X-ray imaging with sub-micrometer resolution was described and it was shown that this setup is very well suited for studying thin samples, especially for biological applications.

The optical stretcher as a tool for single-particle X-ray imaging and diffraction

An optical stretcher was used to trap and manipulate biological cells and latex beads in a microfluidic channel. The trapping capability was used to image isolated suspended cells using X-ray phase-contrast imaging. By rotation of the specimen, even the three-dimensional phase shift of a cell could be recovered.

Absorption, refraction and scattering retrieval in X-ray analyzer-based imaging

A three-image algorithm is proposed for simultaneous retrieval of absorption, refraction and ultra-small-angle scattering information in X-ray analyzer-based imaging. The novel algorithm is theoretically derived, and validated by synchrotron radiation experiments. Furthermore, the effect of angular mis-alignment on the accuracy of the retrieved images is theoretically investigated.

Multiscale X-ray imaging using ptychography

A detailed description of an imaging protocol which integrates both near- and far-field ptychography with full-field and scanning transmission X-ray microscopy in multiscale imaging experiments at synchrotron endstations is given.

Direct information retrieval after 3D reconstruction in grating-based X-ray phase-contrast computed tomography

The theoretical framework of the direct information retrieval method is presented in phase-contrast computed tomography. Numerical simulations are also performed, which reveal that the proposed method provides comparable results of the reverse projection method with short computational time. Furthermore, the compatibility with the existing data preprocessing methods and iterative reconstruction algorithms is discussed.

Atmospheric coherent X-ray diffraction imaging for in situ structural analysis at SPring-8 Hyogo beamline BL24XU

A coherent X-ray diffraction imaging (CXDI) system for structural analysis under atmospheric conditions has been constructed at SPring-8 Hyogo beamline BL24XU. This article reports on the current status of the atmospheric CXDI system, including an attempt towards in situ investigation of structural changes in materials under controlled humidity.

SwissFEL Aramis beamline photon diagnostics

The photon diagnostics available at the SwissFEL Aramis beamline are described. The working principles of various devices, their function and their expected or measured performance are discussed.

ID30B – a versatile beamline for macromolecular crystallography experiments at the ESRF

ID30B, a versatile macromolecular crystallography beamline at the ESRF, is presented.

Xi-cam: a versatile interface for data visualization and analysis

Xi-cam is a graphical environment for synchrotron data analysis, management and visualization.

The simple physics of the bending magnet spectrum

The Doppler effect and its dependence on direction explain key spectral features of the emission of bending magnets in synchrotron sources.