Improved High Resolution Electron Gun for Television Cameras

1963 ◽  
Vol 72 (10) ◽  
pp. 792-794
Author(s):  
S. Gray ◽  
P. C. Murray ◽  
O. J. Ziemelis
Keyword(s):  
High Resolution ◽  
Electron Gun ◽  
Resolution Electron

Development of Field Emission Electron Gun for High Resolution 100KV Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 430-431 ◽  
Author(s):  
T. Someya ◽  
T. Goto ◽  
Y. Harada ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Field Emission ◽  
High Resolution Electron Microscopy ◽  
Electron Gun ◽  
Emission Source ◽  
Resolving Power ◽  
Emission Electron ◽  
Resolution Electron

The field emission source is one of the most important factors to improve the image contrast in extremely high resolution electron microscopy since it provides high brightness, very small electron source and low energy spread of electrons. In scanning electron microscopy, although the field emission source has been proved to be advantageous in the range of relatively low accelerating voltages, those capable of operating at higher accelerating voltages are now in great demand in order to improve the resolving power up to 3Å or better. In the present work, we have developed a field emission electron gun which is used with an electron microscope of accelerating voltages up to 100KV.In this development, we first made efforts to improve the method of supplying high voltages in order to eliminate the surge influence on the field emission source which are easily destroyed by a high voltage surge produced by the discharge between electrodes constituting the electron gun.

High-resolution electron gun

1960 ◽  
Vol 7 (2) ◽  
pp. 112-112
Author(s):  
P.H. Gleichauf
Keyword(s):  
High Resolution ◽  
Electron Gun ◽  
Resolution Electron

Principles and performance of a 600 kV high resolution electron microscope

1980 ◽  
Vol 370 (1740) ◽  
pp. 1-16 ◽  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Gun ◽  
Resolving Power ◽  
Objective Lens ◽  
Optical Parameters ◽  
Resolution Electron ◽  
Pneumatic Suspension ◽  
High Resolution Electron Microscope ◽  
And Performance

The resolving power of the electron microscope as assessed by purely electron optical factors is of the order of 1 Å. The resolution obtainable in practice is limited by adventitious instabilities, mechanical and electrical in nature. The detailed design of a high resolution microscope follows from an analysis of these disturbances; its construction must be carried out with the highest precision. Special attention is paid to the electron gun, to the specimen stage and to the mounting of the microscope. For the Cambridge project, 600 kV has been adopted on the grounds of cost- effectiveness. It employs a lanthanum boride cathode and high stability electronics. A pneumatic suspension system supports the microscope when in operation, to isolate it from ambient vibrations. From the electron optical parameters of the condenser-objective lens, together with the recorded levels of residual disturbances, an image reso¬lution of 2.0 Å is predicted (at 600 kV), which should be improved to 1.5 Å by image processing. Initial results from thin specimens of minerals, metal particles and metallic glasses demonstrate that this performance is already closely approached.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

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