scholarly journals Fresnel Diffraction Pattern and the Electron Microscope

Nature ◽  
1950 ◽  
Vol 166 (4217) ◽  
pp. 338-338
Keyword(s):  
Electron Microscope ◽  
Diffraction Pattern ◽  
Fresnel Diffraction

Using the TEM Condenser Lens to Switch between Image and Diffraction Modes

2013 ◽  
Vol 21 (2) ◽  
pp. 40-40
Author(s):  
Lydia Rivaud
Keyword(s):  
Electron Microscope ◽  
Diffraction Pattern ◽  
Transmission Electron Microscope ◽  
Condenser Lens ◽  
Selected Area Diffraction Pattern ◽  
Transmission Electron ◽  
Set Up ◽  
Convergent Beam ◽  
Beam Diffraction ◽  
Convergent Beam Diffraction

Central to the operation of the transmission electron microscope (TEM) (when used with crystalline samples) is the ability to go back and forth between an image and a diffraction pattern. Although it is quite simple to go from the image to a convergent-beam diffraction pattern or from an image to a selected-area diffraction pattern (and back), I have found it useful to be able to go between image and diffraction pattern even more quickly. In the method described, once the microscope is set up, it is possible to go from image to diffraction pattern and back by turning just one knob. This makes many operations on the microscope much more convenient. It should be made clear that, in this method, neither the image nor the diffraction pattern is “ideal” (details below), but both are good enough for many necessary procedures.

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.

Electron Image Series Reconstruction of Twin Interfaces in InP Superlattice Nanowires

2011 ◽  
Vol 17 (5) ◽  
pp. 752-758 ◽  
Author(s):  
Martin Ek ◽  
Magnus T. Borgström ◽  
Lisa S. Karlsson ◽  
Crispin J.D. Hetherington ◽  
L. Reine Wallenberg
Keyword(s):  
Electron Microscope ◽  
Diffraction Pattern ◽  
Transmission Electron Microscope ◽  
Interface Structure ◽  
Twin Structure ◽  
Twin Interface ◽  
Transmission Electron ◽  
Electron Image ◽  
Model Structures ◽  
Aberration Corrected

AbstractThe twin interface structure in twinning superlattice InP nanowires with zincblende structure has been investigated using electron exit wavefunction restoration from focal series images recorded on an aberration-corrected transmission electron microscope. By comparing the exit wavefunction phase with simulations from model structures, it was possible to determine the twin structure to be the ortho type with preserved In-P bonding order across the interface. The bending of the thin nanowires away from the intended ⟨110⟩ axis could be estimated locally from the calculated diffraction pattern, and this parameter was successfully taken into account in the simulations.

Method of measuring linear displacements of objects based on Fresnel diffraction pattern position

2017 ◽  
Author(s):  
Anvar K. Zakirov ◽  
Alexander N. Ivanov ◽  
Ksenia V. Nizhegorodova ◽  
Ramil I. Minnigazimov ◽  
Vyacheslav V. Porokhin
Keyword(s):  
Diffraction Pattern ◽  
Fresnel Diffraction

Image and Diffraction Pattern Rotations in the TEM

2012 ◽  
Vol 20 (5) ◽  
pp. 52-55
Author(s):  
Graham J.C. Carpenter
Keyword(s):  
Electron Microscope ◽  
Diffraction Pattern ◽  
Transmission Electron Microscope ◽  
Image Rotation ◽  
Spiral Path ◽  
Transmission Electron ◽  
Pass Through ◽  
Computer Processor ◽  
Focused Beam ◽  
Imaging Plane

When electrons pass through the electromagnetic lenses in a transmission electron microscope (TEM), they follow a spiral path that results in image rotation. In many TEMs, the image or diffraction pattern that appears at the final imaging plane has therefore suffered a significant rotation compared to the actual specimen. The extent of the rotation is equal to the sum of the contributions from each lens. In some recent instruments an extra lens is built into the column to compensate for these rotations. In the case of a scanning TEM (STEM), where the image is created by scanning a focused beam on the specimen, the orientation of the image to the specimen is fixed but can be controlled electronically by the computer processor.

XIV.—Experiments in Diffraction Microscopy

1952 ◽  
Vol 63 (3) ◽  
pp. 193-221 ◽  
Author(s):  
G. L. Rogers
Keyword(s):  
Diffraction Pattern ◽  
Elementary Theory ◽  
Focal Length ◽  
Fresnel Diffraction ◽  
Optical Methods ◽  
Zone Plate ◽  
Preliminary Trial ◽  
Adequate Information ◽  
Power Rate ◽  
Diffraction Microscopy

SynopsisExperiments have been performed, using purely optical methods, to verify and extend the theory of Gabor's diffraction microscope. An elementary theory of the process is first given, from which certain generalizations are provisionally drawn. In particular, a focal length is attributed to any Fresnel diffraction pattern and the hologram derived from it by photography. The variation of this focal length with wavelength and scale factor is postulated by analogy with a zone-plate, and the power-rate for a hologram is denned. These deductions are then verified by experiment, and a summary is given at the end of § 10. Various other confirmatory experiments are then described.Adequate information is given about apparatus and technique to enable new entrants into this field to obtain satisfactory results with the minimum of preliminary trial.

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