Radiation damage to macromolecules: kill or cure?

Radiation damage during X-ray data collection remains a challenge in structural biology. Eight papers in the Special Issue are placed in the context of recent research in this area.

Identifying and qu­antifying radiation damage at the atomic level

A metric indicating the relative level of specific radiation damage for individual atoms, that can be calculated from refined and deposited protein structure models, is presented.

Radiation damage to nucleoprotein complexes in macromolecular crystallography

Quantitative X-ray induced radiation damage studies employing a model protein–DNA complex revealed a striking partition of damage sites. The DNA component was observed to be far more resistant to specific damage compared with the protein.

Indications of radiation damage in ferredoxin microcrystals using high-intensity X-FEL beams

High-dose serial femtosecond crystallography experiments were performed on microcrystals of the metalloprotein ferredoxin. Indications of radiation damage to the two [4Fe–4S] clusters are observed.

XFEL diffraction: developing processing methods to optimize data quality

Bragg spots recorded from a still crystal necessarily give partial measurements of the structure factor intensity. Correction to the full-spot equivalent, relying on both a physical model for crystal disorder and postrefinement of the crystal orientation, improves the electron density map in serial crystallography.

Towards RIP using free-electron laser SFX data

Experimental phasing remains an important technical goal in free-electron laser (FEL) serial femtosecond crystallography (SFX) experiments. Here, it is shown that simulated native SFX cathepsin B data can be phased by rapid changes to atomic scattering factors induced by FEL pulses.

Simulations of radiation damage as a function of the temporal pulse profile in femtosecond X-ray protein crystallography

Simulations show that temporal pulse profile is a factor to consider when performing nanocrystallography at free-electron lasers.

On radiation damage in FIB-prepared softwood samples measured by scanning X-ray diffraction

Results of a scanning X-ray diffraction experiment performed on a biological sample prepared with a focused ion beam of gallium atoms are reported for the first time.

Limiting radiation damage for high-brilliance biological solution scattering: practical experience at the EMBL P12 beamline PETRAIII

Simple and effective strategies to curb the effects of radiation damage for solution-based biological SAXS investigations have been implemented for user operations at the EMBL P12 beamline.

New methods in time-resolved Laue pump–probe crystallography at synchrotron sources

Newly developed methods for time-resolved photocrystallographic studies using the polychromatic pink-Laue technique, suitable for medium- and small-size unit cells typical in chemical crystallography, are summarized.

Brightness of synchrotron radiation from undulators and bending magnets

A rigorous theory of the brightness from synchrotron radiation sources based on Wigner distributions is discussed. Results for bending magnets and undulators are compared with those in the literature, highlighting similarities and differences.

Thermal stress prediction in mirror and multilayer coatings

The thermal stresses of multilayer optics under the exposure of synchrotron radiation X-ray white beam are simulated by finite-element analysis.

A new extra-focus monochromator designed for high-performance VUV beamlines

A new monochromator called an extra-focus constant-included-angle varied-line-spacing cylindrical-grating monochromator (extra-focus CIA-VCGM) is described. It is based on the Hettrick–Underwood scheme where the plane varied-line-spacing grating is replaced by a cylindrical one in order to zero the defocus at three reference photon energies in the VUV range.

Pushing the limits: an instrument for hard X-ray imaging below 20 nm

A microscopy system designed and constructed to accommodate multilayer Laue lenses as nanofocusing optics is presented.

The influence of metallic brazing materials on the strain formation of internally water-cooled X-ray optics

A study of metallic brazing material for internally cooled optics is presented, showing the influence of the different material properties on the final quality of the bond in terms of diffracted wavefront distortion, i.e. enlargement of the rocking curve.

Comparative study of the X-ray reflectivity and in-depth profile of a-C, B₄C and Ni coatings at 0.1–2 keV

Reflectivity versus soft X-ray energy and in-depth profiles of chemical elements of a-C-, B₄C- and Ni-coated grazing-incidence mirrors are studied experimentally. The possibility to use B₄C- and Ni-coated mirrors near the carbon K-edge of absorption is demonstrated.

Validation of a Geant4 model of the X-ray fluorescence microprobe at the Australian Synchrotron

The validation of a Geant4 model of the X-ray Fluorescence Microprobe end-station at the Australian Synchrotron is presented.

In situ synchrotron X-ray diffraction investigation of the evolution of a PbO₂/PbSO₄ surface layer on a copper electrowinning Pb anode in a novel electrochemical flow cell

The evolution of the PbO₂ and PbSO₄ surface layers formed on a pure lead anode during electrochemical cycling relevant to electrowinning operations is characterized by in situ synchrotron X-ray diffraction and subsequent Rietveld-based quantitative phase analysis and thickness calculations. The design of a novel reflection geometry electrochemical flow cell is also described.

Noncrystalline structure of Ni–P nanoparticles prepared by liquid pulse discharge

Noncrystalline nickel phosphide nanoparticles have been synthesized, and their morphology, particle size, element contents, local atomic structures, as well as the catalysis in the thermal decomposition of ammonium perchlorate were studied.

Stroboscopic detection of nuclear resonance in an arbitrary scattering channel

The theory of heterodyne/stroboscopic detection of nuclear resonance scattering is developed for various dynamical scattering channels. The grazing-incidence case is discussed in detail and is experimentally demonstrated on isotope periodic and magnetic multilayers.

Effective beam method for element concentrations

A method to evaluate chemical element concentrations in samples by generating an effective polychromatic beam using as initial input real monochromatic beam data is presented.

Planning, performing and analyzing X-ray Raman scattering experiments

A summarising review of data treatment for non-resonant inelastic X-ray scattering data from modern synchrotron-based multi-analyzer spectrometers.

Identification of the iron oxidation state and coordination geometry in iron oxide- and zeolite-based catalysts using pre-edge XAS analysis

The extension of pre-edge peak analysis at the Fe K-edge to catalysis research and operando spectroscopic applications by comparison of high-resolution and conventional X-ray absorption spectra is presented.

⁵⁷Fe polarization-dependent synchrotron Mössbauer spectroscopy using a diamond phase plate and an iron borate nuclear Bragg monochromator

Experimental studies of ⁵⁷Fe polarization-dependent synchrotron radiation Mössbauer spectroscopy using a diamond X-ray phase plate and an iron borate nuclear Bragg monochromator are introduced.

Strategies and limitations for fluorescence detection of XAFS at high flux beamlines

Fluorescence detector strategies are compared for dilute XAFS samples on high flux beamlines.

Ancient administrative handwritten documents: X-ray analysis and imaging

The heavy-element content of ink in ancient administrative documents makes it possible to detect the characters with different synchrotron imaging techniques, based on attenuation or refraction. This is the first step in the direction of non-interactive virtual X-ray reading.

Registration of the rotation axis in X-ray tomography

An improved method for registration of the rotation axis in X-ray tomographic data that takes both tilting and translation errors into consideration is presented.

Profile etching for prefiguring X-ray mirrors

A method to pre-shape mirror substrates using a commercial broad-beam ion source and a contoured mask is presented.

A small and robust active beamstop for scattering experiments on high-brilliance undulator beamlines

Using an indirect detection scheme, a small-size beamstop was developed to accurately measure X-ray beam flux in a wide energy range with reduced radiation level on the electronics and significantly increased in-beam lifetime.

CDApps: integrated software for experimental planning and data processing at beamline B23, Diamond Light Source

CDApps software at Diamond B23 SRCD beamline is presented.

Coherent imaging at the diffraction limit. Erratum

A correction to the article by Thibault et al. [J. Synchrotron Rad. (2014), 21, 1011–1018] is given.

Current events