X-ray Crystal Spectrometers and Monochromators in Microanalysis

2001 ◽  
Vol 7 (2) ◽  
pp. 124-141 ◽  
Author(s):  
David B. Wittry ◽  
Nicholas C. Barbi
Keyword(s):  
Grazing Incidence ◽  
Successful Implementation ◽  
Development Activity ◽  
X Ray ◽  
Basic Physics ◽  
Recent Developments ◽  
History Of ◽  
Point To Point ◽  
Doubly Curved ◽  
Crystal Design

Abstract Castaing’s successful implementation and application of the electron probe microanalyzer in 1950 stimulated a flurry of development activity around the world. The later versions of this instrument represented a truly international effort, with significant contributions by scientists from Europe, Asia, and North America. If the probe-forming system of the instrument was its heart, the X-ray wavelength spectrometer was its soul. This article reviews some of the history of spectrometer developments—lthrough the “golden years” of microprobe development, namely the dozen or so years following the publication of Castaing’s thesis, to the present. The basic physics of spectrometer and crystal design is reviewed. Early experimental devices, such as those developed by Castaing, Borovskii, Wittry, Duncumb, and Ogilvie are reported. Examples of commercial spectrometers such as those by ARL, MAC, Microspec, and Peak are described. Recent developments such as the combination of grazing-incidence optics with flat crystal spectrometers are noted, and the properties and uses of doubly curved crystals are discussed. Finally, the continued development of doubly curved crystal configurations, such as the “Wittry geometry” for scanning monochromators, and point-to-point focusing diffractors for producing small monochromatic X-ray probes to provide improved detection limits for microanalysis are considered.

The Bakerian Lecture 1978 - Cosmic exploration by X-rays

1979 ◽  
Vol 366 (1724) ◽  
pp. 1-21 ◽  
Keyword(s):  
The United States ◽  
National Committee ◽  
Radio Sources ◽  
Cosmic Radio ◽  
The Sun ◽  
X Rays ◽  
X Ray ◽  
Recent Developments ◽  
History Of ◽  
The Subject

Bakerian Lectures dealing with astronomical topics have occurred roughly every ten years during this century. They have therefore something of the character of reports on progress and one need read no further back than Hoyle’s ‘Review of recent developments in cosmology’ (Hoyle 1968) and Ryle’s ‘The nature of the cosmic radio sources’ (Ryle 1958) to discover the background against which are to be seen the dramatic changes of the ensuing period. It stretches from the conception of X-ray astronomy through its birth, with the discovery of the first non-solar source (Giacconi et al . 1962), to its maturity with the availability of satellites to provide long exposures. Nor is it any accident that the root κóσμoς is prominent in the titles of recent lectures for while those of Jeans, Eddington, Milne and Blacket were concerned with our Galaxy, the drama is now truly cosmic. Cosmic X-ray astronomy grew out of the study of the Sun and for this reason its founding father is Herbert Friedman. Giacconi describes well the early history of the subject (Giacconi & Gursky 1974) and tells how, in June 1962, having been interested in the idea by Rossi in September 1959, he and his colleagues detected flux coming neither from the Sun nor from the Moon. Friedman had discussed as early as 1956 ‘how his group obtained puzzling results, which might have been due to celestial X-ray fluxes’, and reported this at the I. A. U. meeting in Moscow in 1958. Stimulated by our solar studies with the Skylark rocket, similar thinking was taking place under the auspices of this Society. Mention of this was made at a conference in the United States in June 1961 (Boyd 1962) but a meeting of the Astronomy Working Group of the British National Committee on Space Research (N. C. S. P./34, 1959 a ) had discussed, in May 1959, the possibility, of mounting ‘Directive X-ray counters’ on the proposed U. K. -I satellite. The minute read ‘Current theories suggested that there may be objects in the sky with strong X-ray emission although inconspicuous visually. A search for these is a matter of great interest and importance.’ It is noteworthy that Hoyle, who had discussed Friedman’s speculations with him, was present at the meeting.

A Brief 100 Year History of Carbon

2017 ◽  
Vol 100 (3) ◽  
pp. 293-298 ◽  
Author(s):  
Terence J. Kemp
Keyword(s):  
Elemental Carbon ◽  
Industrial Revolution ◽  
Materials Science ◽  
Molecular Structures ◽  
Carbon Fibres ◽  
X Ray ◽  
X Ray Crystallography ◽  
Recent Developments ◽  
History Of ◽  
Carbon Molecule

Elemental carbon has been known from time immemorial in its forms of diamond and graphite, while the Industrial Revolution was powered by coal. The molecular structures of diamond and graphite were established following the inception of X-ray crystallography while the complex natures of charcoal and coal have been investigated for 100 years. Recent developments in activated charcoal are described in an article in this issue of Science Progress. However, no-one could have guessed that carbon would have presented such structural surprises as those of C60 fullerene, carbon nanotubes, and graphene. Materials science has benefited from the discovery of carbon fibres, and our understanding of the spectroscopy and bonding in the simplest carbon molecule, C2, has reached new depths.

scholarly journals GIDInd: an automated indexing software for grazing-incidence X-ray diffraction data

2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Manuel Peter Kainz ◽  
Lukas Legenstein ◽  
Valentin Holzer ◽  
Sebastian Hofer ◽  
Martin Kaltenegger ◽  
...  
Keyword(s):  
Substrate Surface ◽  
Grazing Incidence ◽  
Unit Cell ◽  
Successful Implementation ◽  
Mathematical Framework ◽  
X Ray Diffraction ◽  
Unknown Parameters ◽  
X Ray ◽  
Fitting Procedure ◽  
Unit Cells

Grazing-incidence X-ray diffraction (GIXD) is a widely used technique for the crystallographic characterization of thin films. The identification of a specific phase or the discovery of an unknown polymorph always requires indexing of the associated diffraction pattern. However, despite the importance of this procedure, only a few approaches have been developed so far. Recently, an advanced mathematical framework for indexing of these specific diffraction patterns has been developed. Here, the successful implementation of this framework in the form of an automated indexing software, named GIDInd, is introduced. GIDInd is based on the assumption of a triclinic unit cell with six lattice constants and a distinct contact plane parallel to the substrate surface. Two approaches are chosen: (i) using only diffraction peaks of the GIXD pattern and (ii) combining the GIXD pattern with a specular diffraction peak. In the first approach the six unknown lattice parameters have to be determined by a single fitting procedure, while in the second approach two successive fitting procedures are used with three unknown parameters each. The output unit cells are reduced cells according to approved crystallographic conventions. Unit-cell solutions are additionally numerically optimized. The computational toolkit is compiled in the form of a MATLAB executable and presented within a user-friendly graphical user interface. The program is demonstrated by application on two independent examples of thin organic films.

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

Lingual Dystonia Treated with Botulinum Toxin - A Case Report

1970 ◽  
Vol 24 (2) ◽  
pp. 75-78
Author(s):  
MA Hayee ◽  
QD Mohammad ◽  
H Rahman ◽  
M Hakim ◽  
SM Kibria
Keyword(s):  
Botulinum Toxin ◽  
Botulinum Toxin A ◽  
Botulinum Toxin Type A ◽  
Botulinum Toxin Type ◽  
X Ray ◽  
Medical College ◽  
Lingual Dystonia ◽  
History Of ◽  
Chest X Ray

A 42-year-old female presented in Neurology Department of Sir Salimullah Medical College with gradually worsening difficulty in talking and eating for the last four months. Examination revealed dystonic tongue, macerated lips due to continuous drooling of saliva and aspirated lungs. She had no history of taking antiparkinsonian, neuroleptics or any other drugs causing dystonia. Chest X-ray revealed aspiration pneumonia corrected later by antibiotics. She was treated with botulinum toxin type-A. Twenty units of toxin was injected in six sites of the tongue. The dystonic tongue became normal by 24 hours. Subsequent 16 weeks follow up showed very good result and the patient now can talk and eat normally. (J Bangladesh Coll Phys Surg 2006; 24: 75-78)

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

New Structure of CTAB Templated Silica Films as revealed by GISAXS coupled to HRTEM

2000 ◽  
Vol 628 ◽  
Author(s):  
Sophie Besson ◽  
Catherine Jacquiod ◽  
Thierry Gacoin ◽  
André Naudon ◽  
Christian Ricolleau ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Grazing Incidence ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Hexagonal Arrangement ◽  
Spherical Micelles

ABSTRACTA microstructural study on surfactant templated silica films is performed by coupling traditional X-Ray Diffraction (XRD) and Transmission Electronic Microscopy (TEM) to Grazing Incidence Small Angle X-Ray Scattering (GISAXS). By this method it is shown that spin-coating of silicate solutions with cationic surfactant cetyltrimethylammonium bromide (CTAB) as a templating agent provides 3D hexagonal structure (space group P63/mmc) that is no longer compatible with the often described hexagonal arrangement of tubular micelles but rather with an hexagonal arrangement of spherical micelles. The extent of the hexagonal ordering and the texture can be optimized in films by varying the composition of the solution.

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