Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

Atomic resolution Z-contrast imaging of bulk crystal surfaces in Scanning Reflection Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 414-415
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Dark Field ◽  
Contrast Imaging ◽  
Crystal Lattices ◽  
Small Probe ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Image Position ◽  
Z Contrast

The success of obtaining atomic-number-sensitive (Z-contrast) images in scanning transmission electron microscopy (STEM) has shown the feasibility of imaging composition changes at the atomic level. This type of image is formed by collecting the electrons scattered through large angles when a small probe scans across the specimen. The image contrast is determined by two scattering processes. One is the high angle elastic scattering from the nuclear sites,where ϕNe is the electron probe function centered at bp = (Xp, yp) after penetrating through the crystal; F denotes a Fourier transform operation; D is the detection function of the annular-dark-field (ADF) detector in reciprocal space u. The other process is thermal diffuse scattering (TDS), which is more important than the elastic contribution for specimens thicker than about 10 nm, and thus dominates the Z-contrast image. The TDS is an average “elastic” scattering of the electrons from crystal lattices of different thermal vibrational configurations,

scholarly journals Soft diffraction at LHC

2018 ◽  
Vol 172 ◽  
pp. 06005
Author(s):  
Jan Kašpar
Keyword(s):  
Elastic Scattering ◽  
Cross Section ◽  
Elastic Cross Section ◽  
Double Diffraction

This contribution reviews and compares various LHC results on soft diffraction, in particular elastic scattering, total, inelastic and elastic cross-section, single and double diffraction.

Z Dependence of Electron Scattering by Single Atoms into Annular Dark-Field Detectors

2011 ◽  
Vol 17 (6) ◽  
pp. 847-858 ◽  
Author(s):  
Michael M.J. Treacy
Keyword(s):  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Cross Section ◽  
Electron Scattering ◽  
Dark Field ◽  
Single Atom ◽  
Single Atoms ◽  
Annular Dark Field ◽  
Annular Detector ◽  
The Cross

AbstractA simple parameterization is presented for the elastic electron scattering cross sections from single atoms into the annular dark-field (ADF) detector of a scanning transmission electron microscope (STEM). The dependence on atomic number, Z, and inner reciprocal radius of the annular detector, q0, of the cross section σ(Z,q0) is expressed by the empirical relationwhere A(q0) is the cross section for hydrogen (Z = 1), and the detector is assumed to have a large outer reciprocal radius. Using electron elastic scattering factors determined from relativistic Hartree-Fock simulations of the atomic electron charge density, values of the exponent n(Z,q0) are tabulated as a function of Z and q0, for STEM probe sizes of 1.0 and 2.0 Å.Comparison with recently published experimental data for single-atom scattering [Krivanek et al. (2010). Nature464, 571–574] suggests that experimentally measured exponent values are systematically lower than the values predicted for elastic scattering from low-Z atoms. It is proposed that this discrepancy arises from the inelastic scattering contribution to the ADF signal. A simple expression is proposed that corrects the exponent n(Z,q0) for inelastic scattering into the annular detector.

Characterization of Pd/V Multilayer Structures by High-Angle Annular Dark-Field Microscopy and High Resolution Tem

1991 ◽  
Vol 238 ◽  
Author(s):  
J. Liu ◽  
Y. Cheng ◽  
G. D. Lewen ◽  
M. B. Stearns
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Dark Field ◽  
Compositional Variation ◽  
High Angle ◽  
Dark Field Microscopy ◽  
Annular Dark Field ◽  
Chemical Modulation ◽  
Substrate Temperatures

ABSTRACTThe structures of e-beam evaporated Pd/V multilayer thin films, which were fabricated at different substrate temperatures, have been characterized by high-angle annular dark-field microscopy and high resolution electron microscopy techniques. X-ray scattering and crosssectional electron microscopy showed that both the Pd and V layers are composed of small textured crystallites with dominant orientations of Pd (111) and V (110). It is found that Pd/V multilayers with high chemical modulation can be fabricated at substrate temperatures around 350 K and at a deposition rate of 0.2 nm/s. Here high-angle annular dark-field microscopy has been shown to provide direct information about the compositional variation of the interlayers of these ML.

UHV-Electron Microscope Study of Monolayer Adsorption Processes

1981 ◽  
Vol 39 ◽  
pp. 204-207 ◽  
Author(s):  
K. Takayanagi
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
In Situ Observation ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Monolayer Adsorption ◽  
Dark Field Microscopy ◽  
Tem Mode ◽  
Adsorption Processes ◽  
Reconstructed Surface

UHV electron microscopy (UHV-EM) has been shown to be a potent method for investigations of surface structures and surface processes both in TEM-TED (transmission electron microscopy and diffraction) and REM-RED (reflection EM and ED) modes. In addition to the same structural informations as RHEED and LEED they give important informations on microtopography of the surfaces and/or adsorbed phases and detailed aspects of heterogeneous surface phenomena. Analyses of Au(111) reconstructed surface structure in TEM mode and atomic steps of Si(111) surface, adsorbed structures and their domains and phase transition processes in REM mode were reported previously. The present paper reports further results of such studies. In REM mode, a new evaporator for in-situ observation of metal deposition on Si(111) and a double tilt specimen holder for diffraction analyses of surface reactions were constructed. In TEM mode, dark field microscopy by forbidden surface reflections and high resolution microscopy (HREM) have been applied.

An Investigation of the Al/n-GaAs Diodes with High Schottky Barrier Heights

1993 ◽  
Vol 318 ◽  
Author(s):  
C-P. Chen ◽  
Y. A. Chang ◽  
T.F. Kuech
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Cross Section ◽  
Ideality Factor ◽  
Schottky Barrier Height ◽  
Dark Field ◽  
Transmission Electron Microscopy Image ◽  
Transmission Electron

ABSTRACTThermally stable Al/n-GaAs Schottky contacts, up to annealing temperature at 500 °C for 20 seconds, have been realized by sputter deposition from an Al target to (100) n-GaAs at a base pressure ∼2×10−7 Torr. The Schottky barrier height was 0.75 eV (0.9 eV) when using the I-V (C-V) method with an ideality factor of 1.09 for the as-deposited samples. The Schottky barrier height increased to 0.97 eV (1.06 eV) with an ideality factor of 1.07 after annealing at 400 °C for 20 seconds. This barrier height, 0.97 eV, is the highest value reported for Al/n-GaAs diodes. The interfacial stability between Al and GaAs has been examined by cross section transmission electron microscopy. A (200) dark field cross section transmission electron microscopy image of the contact after annealing at 600 °C showed that the (Ga,Al)As phase formed at the interface and the enhancement of the Schottky barrier height was due to the formation of this phase.

HEAVY ION EXCITATION OF GIANT RESONANCES: A BRIDGE FROM THE ELASTIC SCATTERING TO THE INELASTIC DATA

1993 ◽  
Vol 08 (11) ◽  
pp. 997-1004
Author(s):  
A. N. F. ALEIXO ◽  
C. A. BERTULANI ◽  
M. S. HUSSEIN
Keyword(s):  
Elastic Scattering ◽  
Cross Section ◽  
Cross Sections ◽  
Giant Resonance ◽  
Heavy Ion ◽  
Elastic Cross Section ◽  
Giant Resonances ◽  
Intermediate Energies ◽  
Ion Collisions ◽  
Novel Method

We develop data-to-data relations involving the giant-resonance cross-sections and the elastic cross-section for heavy ion collisions at intermediate energies. The usefulness of this novel method is shown by applications to the 17 O + 208 Pb at E Lab = 84 MeV/nucleon.

scholarly journals The Elastic Scattering of 20 eV Electrons from Magnesium

1995 ◽  
Vol 48 (1) ◽  
pp. 71 ◽  
Author(s):  
MJ Brunger ◽  
RK Houghton ◽  
PJO Teubner
Keyword(s):  
Elastic Scattering ◽  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Elastic Cross Section ◽  
Complex Phase ◽  
Shift Analysis ◽  
Order Of Magnitude ◽  
Elastic Differential Cross Section

A modulated crossed-beam technique has been used to measure the differential cross section for elastic scattering of electrons from the 31S state in magnesium at an impact electron energy of 20 eV. The cross section was measured over a range of scattering angles from 15� to 1300? Our results agree with the previous experimental cross sections of Williams and Trajmar within the combined uncertainties, however, the present data reduce the uncertainty by about an order of magnitude, thereby allowing a meaningful comparison to be made with the predictions of the various theories. At this time no theory accurately predicts the behaviour of the elastic differential cross section over the whole angular range. A complex phase-shift analysis is applied to the present data to derive the 20 e V integral elastic cross section. This integral cross section is also compared with the results of previous experiment and theory.

Chemical Synthesis of Gold Micro-Bars for Optical Circuitry Applications

MRS Advances ◽  
2017 ◽  
Vol 2 (52) ◽  
pp. 3045-3050
Author(s):  
Erik W. Hobbs ◽  
Mary Sajini Devadas
Keyword(s):  
Electron Microscopy ◽  
Chemical Synthesis ◽  
Copper Ions ◽  
Chemical Reduction ◽  
Dark Field ◽  
Seeded Growth ◽  
Product Mixture ◽  
Dark Field Microscopy ◽  
Chemical Synthesis Route ◽  
Scanning Electron

ABSTRACTThe aim of this research was to establish a reliable chemical synthesis route to produce plasmonic gold micro-bars. Gold micro-bars have been synthesized through chemical reduction in the presence of surfactants: polyvinylpyrrolidone (PVP) and sodium dodecylsulfonate (SDS), and in the presence of a metal cation. Synthesis was executed by varying the concentration of PVP and SDS, and introducing copper ions, and performing seeded growth. Resulting plasmonic gold micro-bars were viewed under dark field microscopy and scanning electron microscopy (SEM) to visualize the nanoparticle product mixture. Energy Dispersive Spectroscopy (EDS) was used to determine composition of the micro-bars. The results indicate that the copper additive method yields the longest micro-bars.

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