Ultra-High Voltage Electron Microscopy (1-3 MeV) of Biological Macromolecules

1972 ◽  
Vol 30 ◽  
pp. 182-183
Author(s):  
William H. Massover
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Biological Macromolecules ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Dark Field Imaging ◽  
Beam Stop ◽  
Imaging Conditions ◽  
Field Imaging ◽  
Very High

Important difficulties persist for high resolution (= pauci-atomic) electron microscopy of biological macromolecules in terms of obtaining (a) higher effective resolution, (b) decreased specimen damage induced by the electron beam irradiation, and (c) adequate image contrast without the use of extraneous contrasting agents. Electron microscopy at elevated accelerating tensions can largely provide a solution to some of these very problems. Use of a 46μm diameter beam stop (at the level of the objective aperture) for 1000 kV, and of a 23μm diameter beam stop for 3000 kV, produces very high contrast dark field imaging conditions that also retain a higher effective resolution than do the previous beam stop methods developed by Dupouy et al.

scholarly journals Annular Dark Field Imaging of Catalyst Nanoparticles in Single Shot Dynamic Transmission Electron Microscopy

2009 ◽  
Vol 15 (S2) ◽  
pp. 1082-1083
Author(s):  
D Masiel ◽  
B Reed ◽  
T LaGrange ◽  
ND Browning
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Single Shot ◽  
Catalyst Nanoparticles ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Field Imaging

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Techniques for Characterising Artificial Layer Structures using Transmission Electron Microscopy

1987 ◽  
Vol 103 ◽  
Author(s):  
W. M. Stobbs
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Changes ◽  
Dark Field ◽  
Multilayer Structures ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Layer Structures ◽  
Quantitative Characterisation ◽  
Field Imaging

ABSTRACTT.E.M. methods are described for the quantitative characterisation of the compositional and structural changes at interfaces and in homo- and hetero-phase multilayer structures. Many of the newer approaches described including the Fresnel and Centre Stop Dark Field Imaging Methods were developed specifically for such characterisations. The range of applications of each of the techniques is assessed as is the importance of delineating the limiting effects of inelastic and inelastic/elastic multiple scattering.

Reflection Electron Microscopy

1975 ◽  
Vol 33 ◽  
pp. 122-123
Author(s):  
P. E. Højlund Nielsen ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Chromatic Aberration ◽  
Dark Field ◽  
Energy Spread ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Dark Field Imaging ◽  
Reflection Electron Microscopy ◽  
Field Imaging

Reflection electron microscopy was widely used before 1960 for the study of surfaces. For the imaging diffuse scattered electrons was applied. For avoiding a severe foreshortening the surface was illuminated and viewed at fairly large angles. That resulted in a large energy spread of the scattered electrons so the resolution was limited to about 500Å due to chromatic aberration. Since such a resolution could be achieved more readily in scanning microscopes, the method was abandoned. However for single crystal surfaces the situation is entirely different. If the surface can be maintained reasonably clean, strong diffraction spots can be obtained and the energy spread in the diffracted beam is usually small; thus the imaging of the surface can be performed in a manner similar to the dark field imaging of a thin crystalline specimen.

Imaging of III-V Compound Superlattices by Hrem and Rem

1986 ◽  
Vol 77 ◽  
Author(s):  
B. C. De Cooman ◽  
J. R. Conner ◽  
S. R. Summerfelt ◽  
S. McKernan ◽  
C. B. Carter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Dark Field ◽  
Contrast Effects ◽  
Cross Sectional ◽  
Dark Field Imaging ◽  
Thin Foils ◽  
High Resolution Tem ◽  
Reflection Electron Microscopy ◽  
Field Imaging

ABSTRACTTwo techniques for the analysis of III-V compound superlattices are examined. It has been proposed that high-resolution TEM of [100]-oriented thin foils would give an improvement in layer contrast compared with [110]-oriented thin foils; it is shown here that the contrast of [100]-oriented superlattices is not necessarily better. Moreover, both high resolution and conventional dark-field imaging may be subject to significant diffraction contrast effects resulting from the bending of the reflecting planes near the surface of the sample. Reflection electron microscopy (REM) of cross-sectional (110) cleavage planes can also yield dark-field superlattice images and selected area RHEED patterns can in principle be used to determine reliably the superlattice strain as surface effects are minimized.

scholarly journals Application of Electron Diffraction to Problems in Biological Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 398-399
Author(s):  
R. M. Glaeser ◽  
G. Thomas ◽  
R. Christensen ◽  
W. G. Brammer
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Biological Materials ◽  
Optical Microscope ◽  
Dark Field ◽  
Image Contrast ◽  
Dark Field Imaging ◽  
Crystalline Amino Acids ◽  
Field Imaging

The role of elastic (Bragg) scattering in relation to contrast and advanced electron microscopy of biological materials has not been investigated in the detail that is now common with inorganic crystals. It is the object of this paper to demonstrate the application of selected area diffraction, dark field imaging and low angle Fourier contrast to biological materials. Essential differences between the mechanisms of diffraction image-contrast are due to the larger lattice spacings in biological structures, which invariably result in Fourier image contrast. Crystals with spacings greater than 10Å can be expected to show Fourier contrast under normal microscope operations.Samples of crystalline amino acids were grown by solvent evaporation on formvar coated specimen grids. Specimen grids were scanned and selected on the basis of appearance in a polarization-optical microscope (see Fig.1). All crystalline amino acids tested were extremely sensitive to damage in the electron beam.

Studies on The Cytoplasmic Ground Substance Using High Voltage Electron Microscopy of Whole Cultured Cells

1980 ◽  
Vol 38 ◽  
pp. 818-821
Author(s):  
K.R. Porter ◽  
K.J. Luby
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Monolayer Culture ◽  
Cultured Cells ◽  
Ground Substance ◽  
High Quality ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Cytoplasmic Ground Substance ◽  
Very High

Cells of several types, when grown and maintained in monolayer culture, will spread on the substrate to be not greater than 1 pm thick in their thinner margins. When fixed with glutaraldehyde and OsO4 and then dried by the critical-point method,these cells can be viewed in the HVEM and stereo images of very high quality can be obtained. Grown directly on formvar-coated gold grids, such cells are quickly and easily prepared for microscopy.

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