Some Recent Developments in the Direct Viewing and High-Speed Recording of X-Ray Diffraction Patterns

1961 ◽  
Vol 5 ◽  
pp. 86-93 ◽  
Author(s):  
G.W. Goetze ◽  
A. Taylor
Keyword(s):  
Fiber Optics ◽  
High Speed ◽  
Reciprocal Lattice ◽  
Analog Computer ◽  
Laue Pattern ◽  
X Ray Diffraction ◽  
X Ray ◽  
Useful Signal ◽  
Recent Developments ◽  
Diffraction Patterns

AbstractExperiments on the application of X-ray image intensifiers of the Fluorex type and of transmission-type secondary electron image intensifies (Astracon tubes) to the direct observation and recording of X-ray diffraction patterns have proved highly successful. Further improvements can be obtained by combining a Fluorex tube directly with an Astracon tube. By this means, the useful signal strength is so improved that movies at standard frame speed can be made which record the changing Laue pattern from a rotating crystal. It is shown how still further improvements are possible if the optical coupling in the system is improved by incorporating a fiber-optics window at the input of the Fluorex-Astracon tube. It is further indicated how a fiber-optics adapter can be used as an analog computer to convert the X-ray diffraction pattern from a single crystal into an exact representation of the reciprocal lattice which can be viewed directly.

scholarly journals High-speed classification of coherent X-ray diffraction patterns on the K computer for high-resolution single biomolecule imaging

2013 ◽  
Vol 20 (6) ◽  
pp. 899-904 ◽  
Author(s):  
Atsushi Tokuhisa ◽  
Junya Arai ◽  
Yasumasa Joti ◽  
Yoshiyuki Ohno ◽  
Toyohisa Kameyama ◽  
...  
Keyword(s):  
High Resolution ◽  
High Speed ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Resolution Single

scholarly journals Improved crystal orientation and physical properties from single-shot XFEL stills

2014 ◽  
Vol 70 (12) ◽  
pp. 3299-3309 ◽  
Author(s):  
Nicholas K. Sauter ◽  
Johan Hattne ◽  
Aaron S. Brewster ◽  
Nathaniel Echols ◽  
Petrus H. Zwart ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Degrees Of Freedom ◽  
Reciprocal Lattice ◽  
Single Shot ◽  
X Ray Diffraction ◽  
Reciprocal Lattice Point ◽  
X Ray ◽  
Structure Factors ◽  
Rotational Degrees Of Freedom ◽  
Diffraction Patterns

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.

X-Ray Diffraction and Transmission Electron Microscopy Study of One-Dimensional Disorder Polytypes in SiC

1982 ◽  
Vol 40 ◽  
pp. 542-543
Author(s):  
M. Dubey ◽  
S. R. Singh ◽  
G. Singh
Keyword(s):  
Reciprocal Lattice ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
X Ray Diffraction ◽  
Lattice Imaging ◽  
One Dimensional ◽  
X Ray ◽  
Structural Modifications ◽  
Transmission Electron ◽  
Diffraction Patterns

Silicon carbide crystallizes into several structural modifications whose c-periodicities vary from 1 nm to more than 100 nm. Its high period structures are found to consist of intergrowth of smaller period structures at the unit cell level. The X-ray diffraction studies show that SiC crystals often possess one-dimensional disorder which is characterized by continuous streaks in X-ray diffraction patterns along ho.1 reciprocal lattice rows. However, it is shown that these streaks can also arise as a result of extremely high c-periodicities of the crystals as their ho.1 spots cannot be resolved easily. This contribution reports the observation of only few representative cases of so-called one-dimensional disordered crystals as observed in their X-ray and electron diffractions with lattice imaging.

scholarly journals SPIND-TC: an indexing method for two-color X-ray diffraction data

2020 ◽  
Vol 76 (3) ◽  
pp. 369-375
Author(s):  
Xuanxuan Li ◽  
Chufeng Li ◽  
Haiguang Liu
Keyword(s):  
Diffraction Data ◽  
X Ray Diffraction ◽  
Indexing Methods ◽  
X Ray ◽  
Source Codes ◽  
Multiple Wavelength ◽  
Indexing Method ◽  
Recent Developments ◽  
Diffraction Patterns ◽  
New Research

Recent developments of two-color operation modes at X-ray free-electron laser facilities provide new research opportunities, such as X-ray pump/X-ray probe experiments and multiple-wavelength anomalous dispersion phasing methods. However, most existing indexing methods were developed for indexing diffraction data from monochromatic X-ray beams. Here, a new algorithm is presented for indexing two-color diffraction data, as an extension of the sparse-pattern indexing algorithm SPIND, which has been demonstrated to be capable of indexing diffraction patterns with as few as five peaks. The principle and implementation of the two-color indexing method, SPIND-TC, are reported in this paper. The algorithm was tested on both simulated and experimental data of protein crystals. The results show that the diffraction data can be accurately indexed in both cases. Source codes are publicly available at https://github.com/lixx11/SPIND-TC.

X-ray diffraction study of a one-dimensional GaAs–AlAs superlattice

1977 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
A. Segmüller ◽  
P. Krishna ◽  
L. Esaki
Keyword(s):  
Elastic Strain ◽  
Lattice Mismatch ◽  
Reciprocal Lattice ◽  
Unit Cell ◽  
Scattering Data ◽  
High Angle ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Diffraction Patterns

Low- and high-angle X-ray diffraction patterns have been obtained from one-dimensional superlattice crystals prepared artificially by alternately depositing predetermined thicknesses of GaAs and AlAs, on the (001) face of a GaAs single-crystal by molecular-beam epitaxy. The positions and intensities of several superlattice reflections obtained along the 00l, 11l and 02l reciprocal lattice rows have been recorded. The structure of the superlattice can be approximated by a model which incorporates elastic strains in the unit cell due to the lattice mismatch between GaAs and AlAs. The number of Ga and Al layers in the superlattice unit cell can be accurately determined from the low-angle scattering data while the relative intensities of the high-angle superlattice reflections are a sensitive measure of the elastic strain present in the lattice. It is shown that the elastic strain agrees with the value computed theoretically on the assumption that the strain is not relieved by dislocations at the GaAs–AlAs interfaces.

In Situ Analysis of the Formation of thin TISI2, (>50 nm) Contacts in Submicron Cmos Structures during Rapid Thermal Annealing

1995 ◽  
Vol 402 ◽  
Author(s):  
L. A. Clevenger ◽  
C. Cabral ◽  
R. A. Roy ◽  
C. Lavoie ◽  
R. Viswanathan ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
High Speed ◽  
Formation Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Patterned Structures ◽  
Millisecond Time Scale ◽  
Diffraction Patterns

AbstractA detailed in situ study of silicide reactions during rapid thermal annealing of patterned structures was performed to determine the effects of linewidth (0.2 to 1.1 μm), dopants (arsenic, boron or phosphorus) and silicon substrate type (poly-Si or <100>-Si) on the C49 to C54-TiSi2 transformation. A synchrotron x-ray source and a high speed position sensitive detector were used to collect x-ray diffraction patterns of the reacting phases on a millisecond time scale, in situ, during annealing. We demonstrate that most patterned C49-TiSi2 structures (0.2 to 1.1 μm in width, 2 to 4 μm2 in area) will incompletely transform into C54-TiSi2 during rapid thermal annealing. The C49 to C54 transformation ends at about 900°C and further annealing to higher temperatures does not force the remaining C49 to transform into C54. We also observed that the C54 formation temperature increases as the linewidth of the silicide structure decreases. These results are explained by a low density of C54 nuclei in C49 which leads to a one-dimensional growth of C54 grains along the length of the patterned lines. Finally the incorporation of a Mo implant into either poly-Si or <100>-Si before the deposition of titanium is shown to increase the percentage of C49 that transforms into C54 and also to lower the C54 formation temperature.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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