Dreidimensional abbildende Elektronenmikroskope I. Prinzip der Geräte / Threedimensionally Imaging Electron Microscopes

1972 ◽  
Vol 27 (6) ◽  
pp. 919-929 ◽  
Author(s):  
W. Hoppe
Keyword(s):  
Dark Field ◽  
Imaging Systems ◽  
Atomic Resolution ◽  
Small Object ◽  
Fourier Space ◽  
Bright Field ◽  
Image Construction ◽  
Dark Field Imaging ◽  
Electron Microscopes ◽  
Field Imaging

Abstract Threedimensionally Imaging Electron Microscopes The principles of new electron optical imaging systems will be described which make possible the threedimensional image construction of a small object. Data of threedimensional Fourier space are collected by the registration of several images using primary beams with different tilting angles. The simplest device of such a type - a magnetic fly's eye system - will lead to spherical aberrrations larger than about 20 mm. It will be shown, that there is a good chance to correct “ring zone segment”-systems to reach atomic resolution with or without image-reconstruction-calculations. Not only microscopes with conventional bright field and dark field imaging but also transmission scanning microscopes can be constructed usind these principles.

The Dependence of Sample Thickness on Annular Bright Field Microscopy

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
M.M.G. Latting ◽  
W. Walkosz ◽  
R.F. Klie
Keyword(s):  
Image Quality ◽  
Visual Information ◽  
Specific Property ◽  
Dark Field ◽  
Sample Thickness ◽  
Atomic Resolution ◽  
Imaging Method ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Field Imaging

Annular Bright Field (ABF) is a relatively new method of Scanning Transmission Electron Microscopy (STEM) imaging that is desirable because of its ability to provide additional visual information in terms of showing lightweight atoms, whereas standard dark field imaging does not. In order to better understand the parameters necessary to perfect this method, this research article aimed to study a specific property of this imaging method: the dependence of sample thickness on image quality and atomic resolution. Multislice calculations were utilized to generate atomic potentials that were used to simulate different thicknesses of β-Si3N4. The resulting images were then examined to measure atomic full width at half-maximum (FWHM) in order to have a quantifiable value to support visual selection of the best ABF output image. Comparison of image quality/atomic resolution and FWHM values suggested that as a general trend, as sample thickness increases, atomic resolution and image quality deteriorate, citing Huygens' Principle of Classical Optics via the propagation of spherical electron waves through a vacuum. This study will bring a new awareness to the necessary precision required by researchers' sample preparation during Annular Bright Field imaging to yield the best image of their respective samples.

Influence of spatial and temporal coherences on atomic resolution high angle annular dark field imaging

2016 ◽  
Vol 169 ◽  
pp. 1-10 ◽  
Author(s):  
Andreas Beyer ◽  
Jürgen Belz ◽  
Nikolai Knaub ◽  
Kakhaber Jandieri ◽  
Kerstin Volz
Keyword(s):  
Dark Field ◽  
Atomic Resolution ◽  
High Angle ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Field Imaging

scholarly journals Quantitative Annular Dark-Field Imaging at Atomic Resolution

2016 ◽  
Vol 22 (S3) ◽  
pp. 304-305
Author(s):  
Shunsuke Yamashita ◽  
Shogo Koshiya ◽  
Kazuo Ishizuka ◽  
Koji Kimoto
Keyword(s):  
Dark Field ◽  
Atomic Resolution ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Field Imaging

scholarly journals Signal Retrieval from Non-Sinusoidal Intensity Modulations in X-ray and Neutron Interferometry Using Piecewise-Defined Polynomial Function

2021 ◽  
Vol 7 (10) ◽  
pp. 209
Author(s):  
Simon Pinzek ◽  
Alex Gustschin ◽  
Tobias Neuwirth ◽  
Alexander Backs ◽  
Michael Schulz ◽  
...  
Keyword(s):  
Polynomial Function ◽  
Expectation Maximization Algorithm ◽  
Dark Field ◽  
Imaging Systems ◽  
Differential Phase Shift ◽  
Dark Field Imaging ◽  
Phase Stepping ◽  
Sinusoidal Functions ◽  
Field Imaging ◽  
Physical Signal

Grating-based phase-contrast and dark-field imaging systems create intensity modulations that are usually modeled with sinusoidal functions to extract transmission, differential-phase shift, and scatter information. Under certain system-related conditions, the modulations become non-sinusoidal and cause artifacts in conventional processing. To account for that, we introduce a piecewise-defined periodic polynomial function that resembles the physical signal formation process, modeling convolutions of binary periodic functions. Additionally, we extend the model with an iterative expectation-maximization algorithm that can account for imprecise grating positions during phase-stepping. We show that this approach can process a higher variety of simulated and experimentally acquired data, avoiding most artifacts.

New imaging modes in STEM

1988 ◽  
Vol 46 ◽  
pp. 648-649
Author(s):  
A.V. Jones
Keyword(s):  
Energy Loss ◽  
Dark Field ◽  
Detector System ◽  
Objective Lens ◽  
Acceptance Angle ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Complex Forms ◽  
Field Imaging

The most often quoted advantage of STEM over conventional TEM is the ability to produce multiple simultaneous images by the use of multiple detector systems. In practice, this postulated advantage has seldom been fully utilised, mainly because of the practical difficulties in designing such detector systems.Most STEMs to date have been constructed as two-channel instruments combining annular dark-field imaging with either filtered bright-freld or inelastic imaging. More complex forms of bright-field detector have been employed1, as have parallel-readout systems for energy-loss spectra but the ability of the spectrometer to produce multiple simultaneous images has not been fully utilised.The basis of the problem lies in the fact that the objective lens and the detector system(s) have in most cases been designed by the manufacturers as separate entities in order to simplify the later addition of user-specific detectors. Since the acceptance angle of even the best spectrometers is relatively small, additional post-specimen lenses [with their attendant aberrations] had to be added in order to make full use of the spectrometer.

Precipitation and dislocation decoration via extrinsic gettering of Co, Au and Pt by misfit dislocations in Si/Si-2%Ge epitaxy

1989 ◽  
Vol 47 ◽  
pp. 578-579
Author(s):  
D. M. Lee
Keyword(s):  
Imaging Techniques ◽  
Preceding Paper ◽  
Dark Field ◽  
Misfit Dislocations ◽  
Temperature Dependent ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Weak Beam ◽  
Sample Structure ◽  
Field Imaging

Previous work on the gettering activity of a well defined array of buried interfacial misfit dislocations (MDs) showed that the amount of nickel gettered by MD is dominated by the strong temperature-dependent solubility. Precipitation occurs on or in the immediate vicinity of MDs due to nucleation enhancement by strain effects. High temperature 〈1000°C〉 diffusion of gold resulted in the planar colony precipitates on two {111} planes associated with stacking fault formation. In this contribution, we discuss our continuing research pertaining to cobalt, gold (at low temperature), and platinum gettering by MDs which involves studying the nature of dislocation decoration and impurity precipitation in the Si/Si-2%Ge epitaxial system.All the samples used in this study have a buried Si-2%Ge epitaxial layer of ∼ 2 μm thickness.Co, Au and Pt were deliberately diffused into the wafer. The details of the sample structure and preparation are described in a preceding paper. Two-beam bright field and weak-beam dark field imaging techniques were performed on cross-section TEM specimens.

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