Energy-resolved small-angle neutron scattering from steel

A new analysis technique for energy-resolved small-angle neutron scattering is proposed. The precipitate dimensions in steel determined from fitting the observed neutron attenuation spectra agree with those calculated from conventional fitting of the corresponding small-angle neutron scattering profiles.

Thermal expansion of deuterated monoclinic natrojarosite; a combined neutron–synchrotron powder diffraction study

A combination of time-of-flight neutron diffraction and synchrotron X-ray powder diffraction has been used to investigate the thermal expansion of a synthetic deuterated natrojarosite from 80 to 440 K under ambient-pressure conditions.

Orientation relationships between α-zirconium and δ-hydride within a hydride blister

Both the expected and an additional orientation relationship between α-Zr and δ-hydride in blistered zirconium alloys are explored through the reconstruction of the parent α-Zr phase from electron backscatter diffraction maps of δ-hydride.

On the use of two-time correlation functions for X-ray photon correlation spectroscopy data analysis

Two ways to analyse two-time correlation functions and the implications for the evaluation of the correlation times and functional shape of the correlations for equilibrium and non-equilibrium systems are discussed.

Twin domain imaging in topological insulator Bi₂Te₃ and Bi₂Se₃ epitaxial thin films by scanning X-ray nanobeam microscopy and electron backscatter diffraction

Imaging with surface- and bulk-sensitive electron and X-ray diffraction based microscopic techniques enabled identification of the twin domain distribution of Bi₂Te₃ and Bi₂Se₃ thin films. Correlations between the surface topography and crystal orientation are established.

Crystallographic and optical study of PbHfO₃ crystals

This article details the use of birefringence imaging microscopy and high-resolution X-ray diffraction for determining the symmetries of the phases in PbHfO₃ between room temperature and 870 K.

Structure of epitaxial SrIrO₃ perovskite studied by interference between X-ray waves diffracted by the substrate and the thin film

The unit-cell parameters of metastable orthorhombic SrIrO₃ phases epitaxially stabilized on various substrates (DyScO₃, GdScO₃, NdScO₃ and SrTiO₃) are reported. The atomic coordinates of the SrIrO₃ layers are determined by collecting X-ray diffraction curves of a large number of Bragg peaks. The present method, which is described in detail, utilizes not only the Bragg peak intensities but also the interference between waves diffracted by the substrate and the thin film.

Nanoscale characterization of bis­muth telluride epitaxial layers by advanced X-ray analysis

Methods to implement nanostructured models for dynamical simulation of X-ray diffraction in non-periodic layered materials with large d spacing are described and applied to study the case of bismuth telluride epitaxial films grown on barium difluoride (111) substrates.

Simulations and experimental demonstrations of encoding for X-ray coherent scattering

Examples of encoding for X-ray diffraction experiments are presented. The encoding was shown to recover critical information from the experiments.

Joint small-angle X-ray and neutron scattering data analysis of asymmetric lipid vesicles

Low- and high-resolution scattering length density models for the joint analysis of small-angle neutron and X-ray scattering experiments on asymmetric lipid vesicles are presented.

Three-dimensional texture visualization approaches: theoretical analysis and examples

A basic theory is provided for the creation of orientation representations using three-dimensional visualizations. An extensive set of visualizations in both standard and anaglyph movie format is made available as supplementary material.

Neutron filter efficiency of beryllium and magnesium fluorides

First-principles calculations are used to study the vibrational properties of MgF₂ and BeF₂. The calculated phonon densities of states are used to study the thermal neutron inelastic scattering cross sections as a function of neutron incident energy and temperature. Comparisons of neutron filter efficiencies and neutron transmissions through both materials are reported.

Application of combined multivariate techniques for the description of time-resolved powder X-ray diffraction data

A method combining different multivariate techniques is applied to the analysis of large datasets of time-resolved X-ray powder diffraction patterns. The method is based on time-window statistical total correlation spectroscopy, which, together with evolving factor analysis and multivariate curve resolution, allows for the identification and the description of the time evolution of the crystalline as well as the amorphous fractions in the sample, in a semi-automated fashion.

NIST Standard Reference Material 3600: Absolute Intensity Calibration Standard for Small-Angle X-ray Scattering

The certification of a new NIST standard reference material (SRM) for the calibration of small-angle X-ray scattering intensity is described, including the purpose, use and applicability of the SRM together with limitations and uncertainties in the intensity calibration provided.

X-ray investigation of strained epitaxial layer systems by reflections in skew geometry

The ability and technical requirements for a complex characterization of strained epitaxial layer systems using reflections in skew geometry are discussed for four examples of SiGe/Si(001) structures.

SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles

Comprehensive characterization of the morphology of single-core and multi-core magnetic nanoparticle systems for future use as reference materials for magnetic properties was performed using a combination of small-angle X-ray scattering and static light scattering. The composition of the nanoparticle iron oxide cores was determined using XANES.

Rod-like particles growing in sol–gel processing of 1:1 molar mixtures of 3-glycidoxypropyl­tri­meth­oxy­silane and tetra­eth­oxy­silane

Rod-like particles with constant radius and variable length grow at the first stages of aggregation in the sol–gel processing of 1:1 molar mixtures of 3-glycidoxypropyl­tri­meth­oxy­silane and tetra­eth­oxy­silane. Larger aggregates with higher dimensionality formed by rod-like subunits grow at more advanced degrees of aggregation.

Qu­antification of supplementary cementitious content in blended Portland cement using an iterative Rietveld–PONKCS technique

A Rietveld–PONKCS (partial or no known crystal structure) technique is presented for the determination of the weight percentages of predominantly amorphous supplementary cementitious materials (SCMs) contained in Portland cement–SCM blends.

Debye–Waller coefficient of heavily deformed nanocrystalline iron

Extensive deformation of an iron alloy powder increases the static disorder contribution to the thermal factor, with an increase of ∼20% in the Debye–Waller coefficient observed by both X-ray diffraction and extended X-ray absorption fine structure. Molecular dynamics simulations shed light on the underlying mechanisms, confirming the major role played by the grain boundary.

Scanning X-ray nanodiffraction from ferroelectric domains in strained K_0.75Na_0.25NbO₃ epitaxial films grown on (110) TbScO₃

Scanning X-ray nanodiffraction with 100 nm spatial resolution has been applied to investigate the ferroelectric domain structure of K_0.75Na_0.25NbO₃ epitaxial layers grown on a (110) TbScO₃ substrate using metal–organic chemical vapour deposition. Two variants differing in domain wall alignment and vertical lattice parameters have been identified and independently analysed.

Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry

X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La₃Ga₅SiO₁₄) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. The surface acoustic waves create a dynamical diffraction grating on the crystal surface, which can be used for space–time modulation of an X-ray beam.

The fluence–resolution relationship in holographic and coherent diffractive imaging

In this work the fluence efficiency of two coherent X-ray imaging techniques is studied by numerical experiments. The techniques surveyed are near-field holography and far-field diffraction imaging.

The microstructure of Si surface layers after plasma-immersion He⁺ ion implantation and subsequent thermal annealing

A set of complementary methods (high-resolution X-ray reflectivity, high-resolution X-ray diffraction, transmission electron microscopy and atomic force microscopy) were used to study structural changes in the surface Si layer after high-dose low-energy (2 keV) He⁺ plasma-immersion ion implantation and subsequent thermal annealing. This combination is proved to be a powerful tool for complete structural diagnostics of nanoscale He⁺ ion implanted Si layers, especially in the ultra-low-energy implantation regime.

Nondestructive X-ray diffraction measurement of warpage in silicon dies embedded in integrated circuit packages

X-ray diffraction imaging in both monochromatic and white beam section mode has been used to measure quantitatively the displacement and warpage stress in encapsulated silicon devices.

Effect of screw threading dislocations and inverse domain boundaries in GaN on the shape of reciprocal-space maps

Polar GaN layers containing domains with inverse polarities are studied by means of high-resolution X-ray diffraction and transmission electron microscopy. It is shown how the presence of inversion domain boundaries can be recognized directly from reciprocal-space maps measured by X-ray diffraction.

Synchrotron Bragg diffraction imaging characterization of synthetic diamond crystals for optical and electronic power device applications

Bragg diffraction imaging techniques are described, and their capabilities for studying the quality of diamond substrates and overgrown layers, and the surface damage caused by mechanical polishing, are illustrated by examples.

A quick convergent-beam laboratory X-ray reflectometer using a simultaneous multiple-angle dispersive geometry

An X-ray reflectometer, using a laboratory X-ray source, that can measure the specular X-ray reflectivity curve with a time resolution of 10 s or less was developed. Low reflectivities can be measured accurately because the background can be subtracted from the signal.

Investigation of the multiplet structures and crystal field effects of a TiO₆ 3d¹ cluster based on configuration interaction calculations

Configuration interaction cluster calculations have been performed to investigate the LaTiO₃ Ti L₂₃-edge absorption spectrum, providing a comprehensive understanding of the multiplet structures. Detailed temperature- and polarization-dependent simulations reveal the low-temperature orbital state, the orbital–lattice interactions and the orbital polarizations in the compound.

The real background and peak asymmetry in diffraction on nanocrystalline metals

The analysis of peak asymmetry induced by a size-dependent lattice constant is presented. A method is developed for recovering this size dependency, together with the column length distribution for metal nanocrystals with negligible microstrain broadening.

Scattering intensity limit value at very small angles

The mean value of the scattering density fluctuation must behave asymptotically as V^−1/2 for the scattering intensity limit at the reciprocal-space origin to exist.

How do specimen preparation and crystal perfection affect structure factor measurements by qu­antitative convergent-beam electron diffraction?

The influence of specimen preparation and crystal perfection on the measurement of structure factors and bonding by quantitative convergent-beam electron diffraction is assessed in detail. Whilst CeB₆ is the subject of this study, the findings and methods apply to all hard brittle crystalline materials.

Combined scanning X-ray diffraction and holographic imaging of cardiomyocytes

This article presents scanning small-angle X-ray scattering (SAXS) experiments performed on the actomyosin assemblies in freeze-dried cardiac muscle cells by scanning the sample through a sub-micrometre focused beam. The scanning SAXS experiments were advantageously combined with full-field holographic imaging to complement the X-ray diffraction with real-space imaging.

Qu­antitative evaluation of statistical errors in small-angle X-ray scattering measurements

A model is presented for the errors in small-angle X-ray scattering profiles that takes into account the physics of the measurement process. The model agrees quantitatively with the variations observed in experimental measurements and provides a straightforward prescription to add realistic errors to simulated scattering profiles.

Raoult's law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments

The equilibrium relative humidity values for a number of the most commonly used precipitants in biological macromolecule crystallization have been measured using a new humidity control device. A simple argument in statistical mechanics demonstrates that the equilibrium vapour pressure of a solvent is proportional to its mole fraction in an ideal solution (Raoult's law). The same argument can be extended to the case where the solvent and solute molecules are of different sizes.

Crystal structure of fractionally crystallized waxes isolated from crude oil

A petroleum wax has been extracted from an Indian crude oil and crystallized into two fractions, depending on its solubility in methyl isobutyl ketone–toluene at 298 and 313 K. The crystalline nature of the fractionated waxes has been determined by X-ray diffraction.

λ/2 contamination in X-ray diffraction data – the impact of heavy atoms

Differences in f′ and f′′, absorption and wavelength dispersion are discussed with respect to correction of diffraction data for λ/2 contamination.

Ind_X: program for indexing single-crystal diffraction patterns

A Windows console program, Ind_X, for indexing single-crystal diffraction patterns is presented, and the implemented indexing method is briefly described.

New functions and graphical user interface attached to powder indexing software CONOGRAPH

A powder indexing software, CONOGRAPH, as an integrated system is reported.

Back-exchange of deuterium in neutron crystallography: characterization by IR spectroscopy

The application of IR spectroscopy to the analysis of D₂O/H₂O back-exchange in samples used for neutron crystallography is described.

A new method for qu­antitative phase analysis using X-ray powder diffraction: direct derivation of weight fractions from observed integrated intensities and chemical compositions of individual phases. Corrigendum

Erroneous equations in the paper by Toraya [J. Appl. Cryst. (2016), 49, 1508–1516] are corrected.

Howard D. Flack (1943–2017)

Call for papers on Advanced Neutron Scattering Instrumentation

Recent Advances in the Scientific Research on Ancient Glass and Glaze