A double-radius Gandolfi X-ray camera for the generation of powder-like diffractograms of small single crystals, using an imaging plate detector

2002 ◽  
Vol 35 (1) ◽  
pp. 13-16 ◽  
Author(s):  
H. H. Otto ◽  
W. Hofmann ◽  
K. Schröder

This is a report on the construction and the main features of an X-ray camera following the Debye–Scherrer geometry, combined with a sample mounting and rotation device for single crystals as first suggested by Gandolfi. Doubling of the camera radius and replacing of the wet-film technology by a highly dynamic imaging plate system allows well resolved digital diffraction patterns to be recorded within a short exposure time. Sophisticated calibration, correction and evaluation possibilities are supported by suitable software. Further optional improvements, such as the evacuation of the camera, the adaptation of totally reflecting collimators for an almost parallel primary X-ray beam and a built-in instead of an external imaging plate readout device, will further improve the resolution and peak to background ratio. The simple and versatile apparatus is indispensable for the fast and non-destructive identification of unique mineralogical or technical micro-samples in the form of single-crystal pieces. Initial representative data sets attest to the accuracy, efficiency and sensitivity of the method presented.

1991 ◽  
Vol 35 (A) ◽  
pp. 537-543 ◽  
Author(s):  
Yasuo Yoshioka ◽  
Shin'ichi Ohya

AbstractFor determination of stress in a localized area, we combined a modified single exposure technique and the imaging plate, which is an x-ray digital area detector. With the, single exposure method, stress value is obtained from lattice strains in two directions with a single incident x-ray beam directed at an oblique angle. However, since diffraction data around a whole Debye-Scherrer ring was used in this study, a stress value can be accurately determined in comparison with the single exposure method. We observed the DS ring by use of the imaging plate with requiring only a short exposure time. Lattice strains in many directions on a DS ring were measured by an image analyzer connected to a computer; we verified the effectiveness of this method.


1994 ◽  
Vol 27 (5) ◽  
pp. 722-726 ◽  
Author(s):  
J. Grochowski ◽  
P. Serda ◽  
K. S. Wilson ◽  
Z. Dauter

Two data sets were collected on single crystals of hexamethylenetetramine (urotropin) using a four-circle diffractometer with Cu Kα radiation and an imaging-plate two-dimensional detector with Mo Kα source using the rotation method. Both data sets extend to the same limit of sin θ/λ = 0.62 Å−1, corresponding to a resolution of 0.81 Å. Different processing protocols were employed for the two sets of data. Structure refinements carried out separately with each data set led to equivalent results of comparable accuracy. The imaging-plate scanner was able to provide X-ray data of high quality in a significantly shorter time than the diffractometer.


2000 ◽  
Vol 33 (5) ◽  
pp. 1241-1245 ◽  
Author(s):  
A. Fujiwara ◽  
K. Ishii ◽  
T. Watanuki ◽  
H. Suematsu ◽  
H. Nakao ◽  
...  

A synchrotron radiation X-ray powder diffractometer for samples of very small amount has been developed to collect high-quality diffraction patterns under extreme conditions,i.e.at low temperature and/or high pressure. A new cylindrical imaging plate (CIP) is used as a detector, in addition to a conventional flat-type imaging plate (FIP). By using the CIP system, the diffraction data in a diffraction angle range −44 ≤ 2θ ≤ 122° are collected with a dynamic range of about 106. The alignment of the diffractometer, measurement and analysis are automatically operated by a workstation. A performance test shows that the CIP system has spatial resolution of about 0.07° with a dynamic range of 106. The diffraction pattern of a standard sample of Si measured by the CIP system has high quality; the refinement of the structure reachesRw= 3.68% even in the case of a small amount of sample (about 2 µg) and a short exposure time (60 s). Examples of experiments at low temperatures under ambient and high pressures are also presented.


1983 ◽  
Author(s):  
Bruce A. Horn ◽  
Kim C. Luk ◽  
David M. Thomasson ◽  
Charles E. Finney

1997 ◽  
Vol 29 (1-2) ◽  
pp. 89-101 ◽  
Author(s):  
M. Ermrich ◽  
F. Hahn ◽  
E. R. Wölfel

Two-dimensional detectors have opened a new area for the investigation of both single crystals and polycrystalline materials. The working principle of Imaging Plates is described. Some characteristics and the advantages of an Imaging Plate are discussed using the STOE Imaging Plate Diffraction System for different kinds of X-ray analysis: (i) single crystal diffractometry, (ii) powder diffraction and (iii) stress and texture investigations.


1978 ◽  
Vol 33 (8) ◽  
pp. 918-923 ◽  
Author(s):  
F. Müller ◽  
E. Schulte

Flash-x-ray-diffraction patterns (FXD) with an exposure time of 4 ns of NaCl single crystals compressed by plane shock waves are obtained at pressures of about 30 kbar. From the diffraction patterns the compression is determined and compared with Hugoniot data. During shock load the lattice shows an uniaxial compression. While in case of measurements at the free surface an observation time of only a few nanoseconds is available, this experimental set-up allows an observation time of two microseconds.


2015 ◽  
Vol 48 (6) ◽  
pp. 1943-1955 ◽  
Author(s):  
Antonios Vamvakeros ◽  
Simon D. M. Jacques ◽  
Marco Di Michiel ◽  
Vesna Middelkoop ◽  
Christopher K. Egan ◽  
...  

This paper reports a simple but effective filtering approach to deal with single-crystal artefacts in X-ray diffraction computed tomography (XRD-CT). In XRD-CT, large crystallites can produce spots on top of the powder diffraction rings, which, after azimuthal integration and tomographic reconstruction, lead to line/streak artefacts in the tomograms. In the simple approach presented here, the polar transform is taken of collected two-dimensional diffraction patterns followed by directional median/mean filtering prior to integration. Reconstruction of one-dimensional diffraction projection data sets treated in such a way leads to a very significant improvement in reconstructed image quality for systems that exhibit powder spottiness arising from large crystallites. This approach is not computationally heavy which is an important consideration with big data sets such as is the case with XRD-CT. The method should have application to two-dimensional X-ray diffraction data in general where such spottiness arises.


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