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 ◽  
...  

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.

2013 ◽  
Vol 46 (3) ◽  
pp. 791-794 ◽  
Author(s):  
Catherine Dejoie ◽  
Lynne B. McCusker ◽  
Christian Baerlocher ◽  
Rafael Abela ◽  
Bruce D. Patterson ◽  
...  

The new X-ray free-electron laser source (SwissFEL) that is currently being developed at PSI will provide a broad-bandpass mode with an energy bandwidth of about 4%. By using the full energy range, a new option for structural studies of crystalline materials may become possible. The proof of concept of broad-bandpass diffraction presented here is based on Laue single-crystal microdiffraction and the experimental setup on BL12.3.2 at the Advanced Light Source in Berkeley. Diffraction patterns for 100 randomly oriented stationary crystallites of theMFI-type zeolite ZSM-5 were simulated assuming several bandwidths, and the statistical and structural results are discussed. With a 4% energy bandwidth, the number of reflection intensities measured in a single shot is significantly higher than with monochromatic radiation. Furthermore, the problem of partial reflection measurement, which is inherent to the monochromatic mode with stationary crystals, can be overcome.


Author(s):  
Kannan M. Krishnan

Crystalline materials have a periodic arrangement of atoms, exhibit long range order, and are described in terms of 14 Bravais lattices, 7 crystal systems, 32 point groups, and 230 space groups, as tabulated in the International Tables for Crystallography. We introduce the nomenclature to describe various features of crystalline materials, and the practically useful concepts of interplanar spacing and zonal equations for interpreting electron diffraction patterns. A crystal is also described as the sum of a lattice and a basis. Practical materials harbor point, line, and planar defects, and their identification and enumeration are important in characterization, for defects significantly affect materials properties. The reciprocal lattice, with a fixed and well-defined relationship to the real lattice from which it is derived, is the key to understanding diffraction. Diffraction is described by Bragg law in real space, and the equivalent Ewald sphere construction and the Laue condition in reciprocal space. Crystallography and diffraction are closely related, as diffraction provides the best methodology to reveal the structure of crystals. The observations of quasi-crystalline materials with five-fold rotational symmetry, inconsistent with lattice translations, has resulted in redefining a crystalline material as “any solid having an essentially discrete diffraction pattern”


1989 ◽  
Vol 33 ◽  
pp. 389-396 ◽  
Author(s):  
Y. Yoshioka ◽  
T. Shinkai ◽  
S. Ohya

The development of linear position-sensitive detectors (PSD) has resulted in a large reduction of data acquisition times in the field of x-ray stress analysis. However, we also require two-dimensional (2-D) diffraction patterns for material evaluation. Especially, the microbeam x-ray diffraction technique gives valuable information on the structure of crystalline materials and this technique has been applied to fracture analysis by x-rays. Many kinds of 2-D PSD have been developed that have insufficient spatial resolution. So x-ray film has still been used as a 2-D detector, but it requires relatively long exposure times and then the process after exposure is very troublesome.


2014 ◽  
Vol 369 (1647) ◽  
pp. 20130325 ◽  
Author(s):  
John C. H. Spence ◽  
Nadia A. Zatsepin ◽  
Chufeng Li

The use of coherent X-ray lasers for structural biology allows the use of nanometre diameter X-ray beams with large beam divergence. Their application to the structure analysis of protein nanocrystals and single particles raises new challenges and opportunities. We discuss the form of these coherent convergent-beam (CCB) hard X-ray diffraction patterns and their potential use for time-resolved crystallography, normally achieved by Laue (polychromatic) diffraction, for which the monochromatic laser radiation of a free-electron X-ray laser is unsuitable. We discuss the possibility of obtaining single-shot, angle-integrated rocking curves from CCB patterns, and the dependence of the resulting patterns on the focused beam coordinate when the beam diameter is larger or smaller than a nanocrystal, or smaller than one unit cell. We show how structure factor phase information is provided at overlapping interfering orders and how a common phase origin between different shots may be obtained. Their use in refinement of the phase-sensitive intensity between overlapping orders is suggested.


2014 ◽  
Vol 47 (1) ◽  
pp. 188-197 ◽  
Author(s):  
Changyong Song ◽  
Kensuke Tono ◽  
Jaehyun Park ◽  
Tomio Ebisu ◽  
Sunam Kim ◽  
...  

X-ray free-electron lasers (XFELs) provide intense (∼1012 photons per pulse) coherent X-rays with ultra-short (∼10−14 s) pulse lengths. X-rays of such an unprecedented nature have introduced new means of atomic scale structural investigations, and discoveries are still ongoing. Effective use of XFELs would be further accelerated on a highly adaptable platform where most of the new experiments can be realized. Introduced here is the multiple-application X-ray imaging chamber (MAXIC), which is able to carry out various single-pulse diffraction experiments including single-shot imaging, nanocrystallographic data acquisition and ultra-fast pump–probe scattering for specimens in solid, liquid and gas phases. The MAXIC established at the SPring-8 ångström compact free-electron laser (SACLA) has demonstrated successful applications in the aforementioned experiments, but is not limited to them. Also introduced are recent experiments on single-shot diffraction imaging of Au nanoparticles and serial crystallographic data collection of lysozyme crystals at SACLA.


1999 ◽  
Vol 32 (6) ◽  
pp. 1127-1133 ◽  
Author(s):  
H. Lichtenegger ◽  
M. Müller ◽  
O. Paris ◽  
Ch. Riekel ◽  
P. Fratzl

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.


2014 ◽  
Vol 21 (3) ◽  
pp. 600-612 ◽  
Author(s):  
Yuki Sekiguchi ◽  
Tomotaka Oroguchi ◽  
Yuki Takayama ◽  
Masayoshi Nakasako

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite namedSITENNOhas been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using theSITENNOsuite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles.


1986 ◽  
Vol 1 (1) ◽  
pp. 2-6 ◽  
Author(s):  
J. D. Hanawalt ◽  
H. W. Rinn

In the course of the past few years, X-ray and spectroscopic methods of analysis have found an increasing usefulness at the Dow Chemical Company. There are a large number of different types of problems on which information can be obtained by the variations of apparatus and technic which are possible in these two fields. It is not the purpose of this paper, however, to discuss these methods or applications in general, but to describe in some detail a scheme of classifying and using X-ray diffraction patterns which has been found very helpful in one particular application of X-rays — namely, that of identifying unknown substances by means of their Hull powder diffraction patterns.The inherent power of X-ray diffraction as a practical means of chemical analysis was pointed out a good many years ago. Having a different theoretical basis and depending upon an entirely different technic than other methods, it would be expected to supplement the information to be obtained from other methods and, at times, to be applicable where other methods are not suitable. It appears, however, that the use of this method has not increased at a rate commensurate with its unique and valuable features, and that it is used by relatively few academic and industrial laboratories.


2014 ◽  
Vol 70 (12) ◽  
pp. 3299-3309 ◽  
Author(s):  
Nicholas K. Sauter ◽  
Johan Hattne ◽  
Aaron S. Brewster ◽  
Nathaniel Echols ◽  
Petrus H. Zwart ◽  
...  

X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographicRfactors and sharpening anomalous differences that are near the level of the noise.


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