Two-dimensional position-sensitive gaseous detectors for high-resolution neutron and X-ray diffraction

2002 ◽  
Vol 74 (0) ◽  
pp. s252-s254 ◽  
Author(s):  
M. Marmotti ◽  
M. Haese-Seiller ◽  
R. Kampmann
Keyword(s):  
High Resolution ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Position Sensitive

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

High Resolution Synchrotron X-Ray Diffraction Tomography Of Large-Grained Samples

1996 ◽  
Vol 437 ◽  
Author(s):  
D.P. Piotrowski ◽  
S.R. Stock ◽  
A. Guvenilir ◽  
J.D. Haase ◽  
Z.U. Rek
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Three Dimensional ◽  
Polycrystalline Materials ◽  
Diffraction Tomography ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Image Storage ◽  
X Ray ◽  
Dimensional Distribution

AbstractIn order to understand the macroscopic response of polycrystalline structural materials to loading, it is frequently essential to know the spatial distribution of strain as well as the variation of micro-texture on the scale of 100 μm. The methods must be nondestructive, however, if the three-dimensional evolution of strain is to be studied. This paper describes an approach to high resolution synchrotron x-ray diffraction tomography of polycrystalline materials. Results from model samples of randomly-packed, millimeter-sized pieces of Si wafers and of similarly sized single-crystal Al blocks have been obtained which indicate that polychromatic beams collimated to 30 μm diameter can be used to determine the depth of diffracting volume elements within ± 70 μm. The variation in the two-dimensional distribution of diffracted intensity with changing sample to detector separation is recorded on image storage plates and used to infer the depth of diffracting volume elements.

scholarly journals The finer things in X-ray diffraction data collection

1999 ◽  
Vol 55 (10) ◽  
pp. 1718-1725 ◽  
Author(s):  
J. W. Pflugrath
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Rotation Angle ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Software Suite ◽  
X Ray ◽  
Position Sensitive ◽  
X Ray Background ◽  
Position Sensitive Detectors

X-ray diffraction images from two-dimensional position-sensitive detectors can be characterized as thick or thin, depending on whether the rotation-angle increment per image is greater than or less than the crystal mosaicity, respectively. The expectations and consequences of the processing of thick and thin images in terms of spatial overlap, saturated pixels, X-ray background andI/σ(I) are discussed. Thed*TREKsoftware suite for processing diffraction images is briefly introduced, and results fromd*TREKare compared with those from another popular package.

Design of a Real-Time Two-Dimensional Residual Stress Analyzer

1986 ◽  
Vol 30 ◽  
pp. 523-526
Author(s):  
G. M. Borgonovi
Keyword(s):  
Residual Stress ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Detector Plane ◽  
Flat Detector ◽  
One Dimensional ◽  
X Ray ◽  
State Of Stress ◽  
Position Sensitive ◽  
Position Sensitive Detectors

Measurements of residual stress by X-ray diffraction are usually carried out with diffractometers or with one-dimensional position sensitive detectors. The stress is determined from the displacement of the peak that results from intersecting a diffraction cone at high angle with the line scanned by the detector. If a two-dimensional flat detector is used, the intersection of the diffraction cone with the detector plane is a ring, or section of a ring, which is also slightly displaced by the stress. The suggestion has been made use a two-dimensional detector to determine the surface state of stress.

X-Ray Diffraction Orientation Studies Using Two-Dimensional Detectors

1993 ◽  
Vol 37 ◽  
pp. 367-373 ◽  
Author(s):  
T.N. Blanton
Keyword(s):  
Image Intensifier ◽  
Ccd Camera ◽  
Orientation Distribution ◽  
Sensitive Area ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Storage Phosphor ◽  
X Ray ◽  
Film Image ◽  
Position Sensitive

Two-dimensional detectors utilized in x-ray diffraction studies are described. Film, image intensifier/CCD camera, two-dimensional position-sensitive area, and photostimulable storage phosphor detectors are compared. The storage phosphor detector was found to be well suited for analysis of oriented semicrystalline polyester films. Quantitation of polymer orientation was determined using the Hermans orientation distribution function.

A high resolution position sensitive x-ray MWPX for small angle x-ray diffraction

1981 ◽  
Vol 190 (2) ◽  
pp. 385-394 ◽  
Author(s):  
J.E. Bateman ◽  
J.F. Connolly ◽  
R. Stephenson ◽  
G.J. Tappern
Keyword(s):  
High Resolution ◽  
Small Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Position Sensitive

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

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