A simple specimen holder for the accurate comparison of lattice spacings by x-ray back reflection

1967 ◽  
Vol 44 (1) ◽  
pp. 67-68
Author(s):  
R D Arnell
Keyword(s):  
X Ray ◽  
Back Reflection ◽  
Specimen Holder ◽  
Accurate Comparison

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

1990 ◽  
Vol 48 (2) ◽  
pp. 548-548
Author(s):  
E. B. Steel
Keyword(s):  
High Purity ◽  
High Energy ◽  
Quantitative Chemical Analysis ◽  
Detector Performance ◽  
X Ray ◽  
Detector Sensitivity ◽  
Specimen Holder ◽  
Many Instruments ◽  
Charge Resolution ◽  
Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

The Characterization of Defects in Silicon Carbide Crystals by X-Ray Topography in the Back-Reflection Geometry

2004 ◽  
Vol 230-232 ◽  
pp. 1-16 ◽  
Author(s):  
William M. Vetter
Keyword(s):  
Silicon Carbide ◽  
Computer Algorithms ◽  
Reflection Mode ◽  
X Ray ◽  
Back Reflection ◽  
Device Structures ◽  
Reflection Geometry ◽  
Grade Silicon ◽  
Favorable Conditions

Synchrotron white-beam x-ray topographs taken in the back-reflection mode have proved a powerful tool in the study of defects in semiconductor-grade silicon carbide crystals. Capable of mapping the distribution of axial dislocations across a wafer's area (notably the devastating micropipe defect), it can also provide information on their natures. Under favorable conditions, various other types of defect may be observed in back-reflection topographs of SiC, among which are subgrain boundaries, inclusions, and basal plane dislocations. Observed defect images in backreflection topographs may be simulated using relatively simple computer algorithms based on ray tracing. It has been possible to use back-reflection topographs of SiC substrates with device structures deposited upon them to relate the incidence of defects to device failure.

scholarly journals A prototype handheld X-ray diffraction instrument

2018 ◽  
Vol 51 (6) ◽  
pp. 1571-1585 ◽  
Author(s):  
Graeme Hansford
Keyword(s):  
Sample Preparation ◽  
Mineralogical Composition ◽  
General Purpose ◽  
Performance Criteria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Grained ◽  
Back Reflection ◽  
Promising Area ◽  
Sample Position

A conceptual design for a handheld X-ray diffraction (HHXRD) instrument is proposed. Central to the design is the application of energy-dispersive XRD (EDXRD) in a back-reflection geometry. This technique brings unique advantages which enable a handheld instrument format, most notably, insensitivity to sample morphology and to the precise sample position relative to the instrument. For fine-grained samples, including many geological specimens and the majority of common alloys, these characteristics negate sample preparation requirements. A prototype HHXRD device has been developed by minor modification of a handheld X-ray fluorescence instrument, and the performance of the prototype has been tested with samples relevant to mining/quarrying and with an extensive range of metal samples. It is shown, for example, that the mineralogical composition of iron-ore samples can be approximately quantified. In metals analysis, identification and quantification of the major phases have been demonstrated, along with extraction of lattice parameters. Texture analysis is also possible and a simple example for a phosphor bronze sample is presented. Instrument formats other than handheld are possible and online process control in metals production is a promising area. The prototype instrument requires extended measurement times but it is argued that a purpose-designed instrument can achieve data-acquisition times below one minute. HHXRD based on back-reflection EDXRD is limited by the low resolution of diffraction peaks and interference by overlapping fluorescence peaks and, for these reasons, cannot serve as a general-purpose XRD tool. However, the advantages ofin situ, nondestructive and rapid measurement, tolerance of irregular surfaces, and no sample preparation requirement in many cases are potentially transformative. For targeted applications in which the analysis meets commercially relevant performance criteria, HHXRD could become the method of choice through sheer speed and convenience.

X-ray Polytype Examination of SiC Bulk Crystals in Back-Reflection Geometry

1996 ◽  
Vol 29 (4) ◽  
pp. 378-382
Author(s):  
L. Dressler ◽  
K. Goetz ◽  
J. Kräusslich
Keyword(s):  
Bulk Crystals ◽  
X Ray ◽  
Back Reflection ◽  
Reflection Geometry

Dislocations Nucleating Growth in Liquid Phase Epitaxy of Gallium Arsenide

1993 ◽  
Vol 312 ◽  
Author(s):  
Werner Möhling ◽  
H. Weishart ◽  
E. Bauser
Keyword(s):  
Gallium Arsenide ◽  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
Crystal Surface ◽  
Double Crystal ◽  
Growth Interface ◽  
Growth Step ◽  
Burgers Vector ◽  
X Ray ◽  
Back Reflection

AbstractDislocations in GaAs are analysed by X-ray topography in order to relate their nature to their efficiency in generating growth steps. The analysis is mainly based on comparing double crystal back reflection images of the defects to calculated misorientations of the crystal surface which are caused at the outcrop. All types of dislocations are equally effective provided their Burgers vector has a component normal to the growth interface. Concentric growth step patterns, which develop in varying numbers on different samples are not caused by substrate dislocations.

Leveling Device for Forming X-Ray Specimen

1980 ◽  
Vol 24 ◽  
pp. 369-370
Author(s):  
Vann Y. Won
Keyword(s):  
Air Bubbles ◽  
Plastic Film ◽  
X Ray ◽  
Trapped Air ◽  
Specimen Holder ◽  
Specimen Material ◽  
Accurate Definition ◽  
Analysis Window ◽  
Definition Of ◽  
Open Face

A device was made for preparing accurate definition of surface, depth and volume of liquid x-ray fluorescence specimens.The apparatus used in conjunction with a specimen holder and plastic film window material accurately and consistently forms a flat bobble-free analysis window on the open face of the specimen holder. The specimen holder in the form of a shallow cylinderical cup is slightly over filled and covered by the plastic film. Placement of the mating leveling apparatus over the film squeezes out trapped air bubbles, levels the exposed face of the specimen, draws the plastic film tightly over the exposed face of the specimen and allows easy installation of a film retaining O-ring to maintain the specimen material in a level state within the holder.

Residual Stresses Resulting from the Forming of High Strength Aluminium Alloys

1959 ◽  
Vol 63 (578) ◽  
pp. 90-94
Author(s):  
G. A. Hawkes
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Residual Strain ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
High Strength ◽  
Hot Forming ◽  
X Ray ◽  
Back Reflection ◽  
Surface Residual Stresses

Summary:An X-ray back reflection technique has been used to measure the surface residual stresses resulting from the cold and hot forming of certain high strength aluminium alloys. The alloys examined were to specifications DTD 683, DTD 687 and B.S.S. L65, and the residual stresses have been related to the residual strain in bending of these alloys. The results show that, apart from the degree of straining, the residual stresses are affected by the heat treatment (cold or hot quench) and the amount (if any) of controlled stretching that the alloy has had between solution treatment and precipitation.

A metallographic study of the angra dos Reis (iron) meteorite

1971 ◽  
Vol 38 (293) ◽  
pp. 94-101 ◽  
Author(s):  
H. J. Axon ◽  
C. V. Waine
Keyword(s):  
Electron Microscope ◽  
Diffraction Pattern ◽  
Metallic Matrix ◽  
Iron Meteorite ◽  
X Ray Diffraction ◽  
Metallographic Study ◽  
X Ray ◽  
Back Reflection ◽  
Shock Event

SummaryThe Angra dos Reis (iron) has been studied metallographically and an attempt has been made to discuss the circumstances under which the following elements of structure formed: clear etching and frosty etching kamacite, decorated Neumann lines, giant rhabdites, plate rbabdites, rhabdite clusters, microrhabdites, cohenite, and remelted troilite. The remelted troilite is taken to indicate a shock event. However, since there are no metallographically visible indications of shock in the kamacite and since the back reflection X-ray diffraction pattern shows only very faint Debye-Scherrer arcs superimposed on a pattern of sharp spots, it is concluded that the shock event took place at a temperature that allowed shock effects to anneal out of the kamacite almost completely. A submicroscopic precipitate in the metallic matrix is observable with the electron microscope and may represent the final precipitation of phosphide from shocked kamacite.

Studies of c-Axis Threading Screw Dislocations in Hexagonal SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Yi Chen ◽  
Xianrong Huang ◽  
Ning Zhang ◽  
Govindhan Dhanaraj ◽  
Edward Sanchez ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Grazing Incidence ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Back Reflection ◽  
Partial Dislocations ◽  
Ray Tracing Simulation ◽  
Vector Magnitude

ABSTRACTIn our study, closed-core threading screw dislocations and micropipes were studied using synchrotron x-ray topography of various geometries. The Burgers vector magnitude of TSDs can be quantitatively determined from their dimensions in back-reflection x-ray topography, based on ray-tracing simulation and this has been verified by the images of elementary TSDs. Dislocation senses of closed-core threading screw dislocations and micropipes can be revealed by grazing-incidence x-ray topography. The threading screw dislocations can be converted into Frank partial dislocations on the basal planes and this has been confirmed by transmission synchrotron x-ray topography.

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