Influence of Bragg diffraction on perfect crystal neutron phase shifters and the exact solution of the two-beam case in the dynamical diffraction theory

The theory and measurement of the neutron phase shift, index of refraction or coherent scattering length of perfect crystal samples in a neutron interferometer are described. Residual phase corrections far off-Bragg are identified as local field corrections.

Diffuse scattering intensity near the Bragg reflection in a (para)magnetic bulk face-centred cubic Ni₃Fe-type permalloy

Within the scope of the classical theoretical models, the diffuse scattering intensities (caused by the short-range atomic order) near the Bragg reflection in a (para)magnetic bulk face-centred cubic Ni₃Fe-type permalloy are investigated, taking into account the long-range magnetic order and `strain-induced' effects. The analytic azimuthal and nonanalytic `radial' behaviours of the diffuse intensities as well as the `mixing' energy Fourier components are analysed in detail.

Minimal nets and minimal minimal surfaces

It is shown that the 15 minimal nets can serve as the labyrinth graph of one or other of the five known minimal surfaces of genus 3 and that the enumeration of such surfaces is likely to be complete.

Semi-transparent central stop in high-resolution X-ray ptychography using Kirkpatrick–Baez focusing

A semi-transparent central stop has been used for ptychographic coherent diffractive imaging to increase the effective dynamic range in the recording of the far-field diffraction patterns. In this way, the high flux density provided by nano-focusing Kirkpatrick–Baez mirrors can be fully exploited for high resolution and quantitative phase reconstructions.

One-step model of the face-centred-cubic to body-centred-cubic martensitic transformation

A model of the face-centred-cubic to body-centred-cubic martensitic transformation based on Pitsch distortion explains the continuum of martensite variant orientations observed in electron backscatter diffraction.

On the enumeration of the combinatorial types of primitive parallelohedra in E^d, 2 ≤ d ≤ 6

The cone of positive-definite quadratic forms is subdivided into subcones of combinatorial types of primitive parallelohedra in E^d, 2 ≤ d ≤ 6. An efficient algorithm is described.

Iterative projection algorithms in protein crystallography. I. Theory

A general class of iterative projection algorithms is proposed as a tool for phase determination in protein crystallography. The main iterative projection algorithms are described as well as their potential application to protein crystallography.

Steve Wilkins (1946–2013)

Obituary for Steve Wilkins.

Geometry of Crystallographic Groups