Imaging of the helical arrangement of cellulose fibrils in wood by synchrotron X-ray microdiffraction

1999 ◽  
Vol 32 (6) ◽  
pp. 1127-1133 ◽  
Author(s):  
H. Lichtenegger ◽  
M. Müller ◽  
O. Paris ◽  
Ch. Riekel ◽  
P. Fratzl
Keyword(s):  
Incident Beam ◽  
Special Choice ◽  
Local Orientation ◽  
Cell Axis ◽  
Beam Position ◽  
X Ray ◽  
Diffraction Geometry ◽  
Ewald Sphere ◽  
Cellulose Fibrils ◽  
Diffraction Patterns

A complete image of the helical arrangement of cellulose fibrils in the S2 layer of adjacent wood cells ofPicea abies(Norwegian spruce) was obtained by applying position-resolved synchrotron X-ray microdiffraction on cells in cross section. In contrast to conventional fiber diffraction studies, the incident beam was parallel to the longitudinal cell axis, resulting in a glancing angle μ far from 90° with respect to the cellulose fibrils. This special choice of diffraction geometry allowed us to take advantage of an asymmetry effect in the two-dimensional diffraction patterns arising from the curvature of the Ewald sphere to obtain information on the local orientation of the cellulose fibrils. The small size of the beam, smaller than the thickness of a single cell wall, allowed mesh scans over intact transverse sections of adjacent wood cells with a microscopic position resolution. The scan yielded a map of diffraction patterns that could readily serve as a microscopic image. Each of the diffraction patterns was then used to evaluate the local orientation of the cellulose fibrils at the actual beam position. The combination of these results gave an image of cellulose fibrils forming (Z) helices in several adjacent wood cells.

Theory of bulk resonance diffraction in THEED

1993 ◽  
Vol 440 (1908) ◽  
pp. 95-115 ◽  
Keyword(s):  
Elastic Scattering ◽  
Incident Beam ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Zone Axis ◽  
Bloch Waves ◽  
Diffraction Geometry ◽  
Ewald Sphere ◽  
Lattice Images ◽  
New Type

A full dynamical theory has been developed for an off-axis diffraction geometry. A new type of resonance elastic scattering is found and discussed. This occurs when the Ewald sphere is almost tangential to one of the minus high order Laue zones, and is termed bulk resonance diffraction. It is shown that under certain diffraction conditions, i. e. bulk resonance diffraction conditions, effectively only a single distinct tightly bound Bloch wave localized around atom strings is excited within the crystal, and selection can be made of the particular bound Bloch waves by appropriately tilting the incident beam or the crystal. A new scheme for imaging individual tightly bound Bloch waves is proposed. Full dynamical calculations have been made for 1T–V Se 2 single crystals. It is demonstrated that chemical lattice images of V and Se atom strings can be obtained along the [0001] zone axis of a 1T–V Se 2 crystal for angles of incidence of 109.54 and 109.90 mrad respectively.

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources

2018 ◽  
Vol 25 (3) ◽  
pp. 748-756 ◽  
Author(s):  
M. X. Tang ◽  
Y. Y. Zhang ◽  
J. C. E ◽  
S. N. Luo
Keyword(s):  
Single Crystal ◽  
Large Scale ◽  
Incident Beam ◽  
Wave Structure ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Case Transmission ◽  
Dynamics Simulations

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic–plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of the diffraction patterns is discussed.

Statistical measures of spottiness in diffraction rings

2013 ◽  
Vol 47 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Bridget Ingham
Keyword(s):  
Carbon Dioxide ◽  
Size Distribution ◽  
Intensity Variation ◽  
Incident Beam ◽  
Mean Square ◽  
X Ray Diffraction ◽  
X Ray ◽  
Statistical Measures ◽  
Diffraction Patterns

Spotty diffraction rings arise when the size distribution of crystallites illuminated by the incident beam includes crystallites that are large compared with the size of the beam. In this article, several statistical measures are used in conjunction to quantify spottiness and relate it to a crystallite size distribution: the number of peaks, the normalized root mean square intensity variation and the fractal dimension. These are demonstrated by way of example using synchrotron X-ray diffraction patterns collected duringin situcorrosion of mild steel in carbon dioxide-saturated aqueous brine.

scholarly journals X-ray position-sensitive duo-lateral diamond detectors at SOLEIL

2018 ◽  
Vol 25 (2) ◽  
pp. 399-406 ◽  
Author(s):  
Kewin Desjardins ◽  
Michel Bordessoule ◽  
Michal Pomorski
Keyword(s):  
Collection Efficiency ◽  
Chemical Vapour ◽  
Incident Beam ◽  
Acquisition Time ◽  
Experimental Conditions ◽  
Beam Position ◽  
Charge Collection Efficiency ◽  
Position Resolution ◽  
X Ray ◽  
Position Sensitive

The performance of a diamond X-ray beam position monitor is reported. This detector consists of an ionization solid-state chamber based on a thin single-crystal chemical-vapour-deposition diamond with position-sensitive resistive electrodes in a duo-lateral configuration. The detector's linearity, homogeneity and responsivity were studied on beamlines at Synchrotron SOLEIL with various beam sizes, intensities and energies. These measurements demonstrate the large and homogeneous (absorption variation of less than 0.7% over 500 µm × 500 µm) active area of the detector, with linear responses independent of the X-ray beam spatial distribution. Due to the excellent charge collection efficiency (approaching 100%) and intensity sensitivity (0.05%), the detector allows monitoring of the incident beam flux precisely. In addition, the in-beam position resolution was compared with a theoretical analysis providing an estimation of the detector's beam position resolution capability depending on the experimental conditions (X-ray flux, energy and readout acquisition time).

Application of a single-reflection collimating multilayer optic for X-ray diffraction experiments employing parallel-beam geometry

2008 ◽  
Vol 41 (1) ◽  
pp. 124-133 ◽  
Author(s):  
M. Wohlschlögel ◽  
T. U. Schülli ◽  
B. Lantz ◽  
U. Welzel
Keyword(s):  
Incident Beam ◽  
Grazing Incidence ◽  
Photon Flux ◽  
Data Sets ◽  
Parallel Beam ◽  
X Ray ◽  
Beam Focusing ◽  
Beam Geometry ◽  
Parallel Beam Geometry ◽  
Diffraction Patterns

Instrumental aberrations of a parallel-beam diffractometer equipped with a rotating anode X-ray source, a single-reflection collimating multilayer optic and a parallel-plate collimator in front of the detector have been investigated on the basis of standard measurements (i.e.employing stress- and texture-free isotropic powder specimens exhibiting small or negligible structural diffraction line broadening). It has been shown that a defocusing correction, which is a major instrumental aberration for diffraction patterns collected with divergent-beam (focusing) geometries, is unnecessary for this diffractometer. The performance of the diffractometer equipped with the single-reflection collimating multilayer optic (single-reflection mirror) is compared with the performance of the diffractometer equipped with a Kirkpatrick–Baez optic (cross-coupled Göbel mirror) on the basis of experimental standard measurements and ray-tracing calculations. The results indicate that the use of the single-reflection mirror provides a significant gain in photon flux and brilliance. A high photon flux, high brilliance and minimal divergence of the incident beam make the setup based on the single-reflection mirror particularly suitable for grazing-incidence diffraction, and thus for the investigation of very thin films (yielding low diffracted intensities) and of stress and texture (requiring the acquisition of large measured data sets, corresponding to the variation of the orientation of the diffraction vector with respect to the specimen frame of reference). A comparative discussion of primary optics which can be used to realise parallel-beam geometry shows the range of possible applications of parallel-beam diffractometers and indicates the virtues and disadvantages of the different optics.

Texture Inheritance in a Zn Protective Layer

2004 ◽  
Vol 443-444 ◽  
pp. 189-192 ◽  
Author(s):  
Jan T. Bonarski
Keyword(s):  
Protective Layer ◽  
Incident Beam ◽  
Layered Structures ◽  
Point Of View ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Near Surface ◽  
X Ray ◽  
Diffraction Geometry ◽  
Information Depth

Crystallographic texture is one of frequently investigated properties of near-surface regions. From the application point of view, the inheritance effect of the crystallographic orientation of a substrate is important for layered structures. The investigation of the texture of layered structures or gradient materials by means of X-ray diffraction back-reflection pole figure measurements requires a control of the information depth. Such measurements at a controlled information depth can be achieved by means of non-symmetrical diffraction geometry, employing a constant value of falling angle of the incident beam. Thus, the texture of near-surface layers with a defined thickness can be examined, as in tomographic techniques. In this work, the method of texture analysis based on a controlled information depth was applied to the investigation of the texture inheritance of a Zn protective layer on deep drawing steel. Moreover, the crystallographic relations between the texture of substrate and deposited layer, termed as texture inheritance, were considered.

Lattice and Peak Profile Parameters in GIXD Technique

2007 ◽  
Vol 130 ◽  
pp. 281-286 ◽  
Author(s):  
Tomasz Goryczka ◽  
Grzegorz Dercz ◽  
Lucjan Pająk ◽  
Eugeniusz Łągiewka
Keyword(s):  
Structural Parameters ◽  
Incident Beam ◽  
Half Width ◽  
Diffraction Line ◽  
Beam Angle ◽  
X Ray Diffraction ◽  
Parallel Beam ◽  
X Ray ◽  
Diffraction Patterns ◽  
Α Angle

Grazing incident X-ray diffraction technique was applied to determine the influence of incident beam angle (α angle) on structural parameters as well as peak profile. X-ray diffraction patterns were registered in asymmetrical geometry, in which a parallel beam was formed by Soller and divergence slits. Lowering of the α angle results in accuracy decrease of lattice parameters as well as in significant broadening of a half-width of X-ray diffraction line.

scholarly journals Serial snapshot crystallography with a non-monochromatic microbeam

2014 ◽  
Vol 70 (a1) ◽  
pp. C294-C294
Author(s):  
Catherine Dejoie ◽  
Lynne McCusker ◽  
Christian Baerlocher ◽  
Rafael Abela ◽  
Bruce Patterson ◽  
...  
Keyword(s):  
Energy Range ◽  
Simulated Data ◽  
Single Pulse ◽  
Finite Width ◽  
Single Shot ◽  
Crystalline Materials ◽  
X Ray ◽  
Reflection Measurement ◽  
Ewald Sphere ◽  
Diffraction Patterns

X-ray free-electron laser (XFEL) sources create X-ray pulses of unprecedented brilliance and open up new possibilities for the structural characterization of crystalline materials. By exposing a small crystallite (100nm-10μm) to a single ultrafast pulse, a diffraction pattern can be obtained before the crystal is damaged. If such single-pulse diffraction patterns, collected sequentially on many randomly oriented crystallites, are combined, it is possible to determine the structure of the material accurately [1]. One of the drawbacks of this approach is that only a single position of the Ewald sphere is accessed in each pattern, so, because reflections have a finite width, the diffraction condition is not satisfied completely for any of the reflections recorded. The new XFEL source that is being developed in Switzerland (SwissFEL) will provide a broad-bandpass mode with an energy bandwidth of about 4% [2]. By using the full energy range of the SwissFEL beam, a new option for structural studies of crystalline materials becomes possible. In a recent study based on simulated data, we showed that a diffraction experiment with stationary crystallites in such an `extra pink' beam not only increases the number of reflection intensities that can be collected in a single shot, but also overcome the problem of `partial reflection' measurement [3]. To test the viability of the data processing with experimental data, attempts to simulate this 4% bandpass have been carried out on SNBL at ESRF and on the microXAS beamline at SLS. On SNBL, a single crystal was rotated over 360° and a continuous scan of the monochromator over the 4% energy range was performed every 1°. At SLS, a mirror was used to cut off the higher energies of the undulator beam and the energy threshold of a Pilatus detector to eliminate the lower ones. With this setup, a series of randomly oriented crystallites were measured. A comparison of the analysis of these datasets will be presented.

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