issue contents

Journal logoJOURNAL OF
SYNCHROTRON
RADIATION
ISSN: 1600-5775

July 2018 issue

Includes papers presented at Q2XAFS2017 - the International Workshop on Improving Data Quality in XAFS Spectrometry, Diamond Light Source, UK, 14-15 August 2017

Guest editors: Sofia Diaz-Moreno and Richard W. Strange

Highlighted illustration

Cover illustration: The logo of the Q2XAFS2017 workshop that was held at Diamond Light Source, UK, 14-15 August 2017.

facility information


q2xafs2017 workshop


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

link to html
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.

link to html
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.

link to html
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.

link to html
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.

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

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

link to html
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.

link to html
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.

link to html
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.

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

research papers


link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
X-ray absorption spectroscopy was applied to study the enhanced insulating behavior in the Ir-vacant Sr2Ir1–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 Sr2Ir1–xO4.

link to html
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.

link to html
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.

link to html
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.

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


link to html
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.

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

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

link to html
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.

beamlines


link to html
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.

computer programs


teaching and education


link to html
The Doppler effect and its dependence on direction explain key spectral features of the emission of bending magnets in synchrotron sources.
Follow J. Synchrotron Rad.
Sign up for e-alerts
Follow J. Synchrotron Rad. on Twitter
Follow us on facebook
Sign up for RSS feeds