Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

1969 ◽  
Vol 27 ◽  
pp. 418-419 ◽  
Author(s):  
R. C. Moretz ◽  
D. F. Parsons
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Structural Damage ◽  
Lower Percentage ◽  
Vacuum Drying ◽  
Total Removal ◽  
Total Absence ◽  
Biological Studies ◽  
Electron Microscopes ◽  
Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

A New High Intensity Grid Cap for RCA-EMU-3 Electron Microscopes

1968 ◽  
Vol 26 ◽  
pp. 316-317
Author(s):  
George Christov ◽  
Bolivar J. Lloyd
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Voltage ◽  
High Intensity ◽  
Electron Gun ◽  
Tungsten Filament ◽  
Fluorescent Screen ◽  
Electron Microscopes ◽  
Pass Through ◽  
Ground Potential

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.

Nanoprobing Beyond 14 nm with Latest Generation SEM-Based Nanoprobers

2017 ◽  
Author(s):  
Noor Jehan Saujauddin ◽  
Esther P.Y. Chen ◽  
Felix Beaudoin
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Measurement Time ◽  
Electrical Connection ◽  
Previous Generation ◽  
Damage Imaging ◽  
Imaging Resolution ◽  
Beam Damage ◽  
Scanning Electron

Abstract As the technology scales down, SEM (Scanning Electron Microscope) based nanoprobing faces challenges. Transistors are more susceptible to electron beam damage. As SEM energy decreases to prevent damage, imaging resolution degrades, making it increasingly more difficult to position the probe tips on the contacts. Once landed, the probe stability is important to maintain a good electrical connection throughout the measurement time. We review how well one of the latest generation nano probers addresses these challenges on sub 14nm transistors. Results are compared with a previous generation tool to illustrate the improved imaging and stability capabilities.

The limits of microanalytical information as set by electron-beam damage

1983 ◽  
Vol 41 ◽  
pp. 366-367
Author(s):  
M. S. Isaacson
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
General Practitioner ◽  
Radiation Damage ◽  
To Come ◽  
Main Item ◽  
Electron Microscopist ◽  
Beam Damage

The task given to me was try to address how radiation damage limits the information that we can extract from a sample in the electron microscope and to somehow i11ucidate what is known about the mechanism of the damage itself. I am afraid that the tasks are more formidable than I first realized, and I shall not (in this paper) be able to come to definitive conclusions. However, the attempt will be made to tie together various observations and bits of knowledge from different areas which may not be familiar to the general practitioner of electron microscopy.The area of radiation damage in electron microscopy tends to be somewhat descriptive. After all, it is really not the main item on the microscopist's agenda, but rather happens to be the unfortunate consequence of the act of viewing the sample. One can liken the electron microscopist to someone who is ill. It is not too important why or how the illness occurred, but rather, how to remedy it.

The Role of Temperature in Limiting Radiation Damage to Organic Materials in Electron Microscopes

1990 ◽  
Vol 48 (2) ◽  
pp. 404-405
Author(s):  
M.K. Lamvik
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
Radiation Damage ◽  
Organic Materials ◽  
Charged Particles ◽  
High Flux ◽  
Electron Sources ◽  
Electron Microscopes

The intensity of the electron beam in an electron microscope is at once the basis for progress as well as the ultimate limitation in electron microscopy of organic materials. Gabor noted that the highest intensity available for light optics comes from sunlight, which produces an energy density of 2,000 watts/cm2-steradian. The electron sources in early microscopes could produce a million times that amount, and modern sources even more. While the high intensity made good images possible (because numerical apertures used for electron microscopes are less than 1% of the size used in light microscopy) early microscopists feared that such a high flux of charged particles would destroy most specimens, especially organic ones. Although it was soon found that biological specimens could survive observation by electron microscopy, the introduction of double-condenser illumination systems revealed the problem of specimen contamination. In time it became clear that radiation damage was more fundamental than the gross increases or decreases in specimen mass observed in contamination and etching.

Electron-beam damage and analysis at low temperature

1990 ◽  
Vol 48 (4) ◽  
pp. 806-807
Author(s):  
Yoshio Bando ◽  
Yoshizo Kitami ◽  
Masato Yokoyama
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Low Temperature ◽  
Mass Loss ◽  
Radiation Damage ◽  
Liquid Helium ◽  
Inorganic Materials ◽  
Specimen Holder ◽  
Analytical System ◽  
Beam Damage

Elemental analysis for beam-sensitive materials is limited by radiation damage due to inelastic scattering of electrons. The amorphization and the mass loss often occure during the observation under a focused electron beam. It has been so far understood that the electron beam damage is effectively reduced by decreasing the specimen temperature. The cryo-electron microscope using liquid helium colled specimen holder is useful to minimize the radiation damage of the beam-sentitive materials. In the present paper, we have studied the radiation damage of various insulating inorganic materials in terms of the rate of the amorphization and the selective mass loss, which are observed at a room temperature (300K) and a low temperature (20K). All measurements are performed on a JEM-4000FX high-resolution analytical electron microscope with full analytical system. The specimen fragments placed on a holey carbon supporting grid are cooled down to about 20K. using a liquid helium specimen holder attached with a Be retainer.

scholarly journals Phosphorene under electron beam: from monolayer to one-dimensional chains

Nanoscale ◽  
2016 ◽  
Vol 8 (15) ◽  
pp. 7949-7957 ◽  
Author(s):  
Ville Vierimaa ◽  
Arkady V. Krasheninnikov ◽  
Hannu-Pekka Komsa
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
One Dimensional ◽  
Beam Damage

Calculations for electron beam damage in phosphorene yield limits to stability in electron microscope and propose ways to beam engineering.

Sign in / Sign up

Export Citation Format

Share Document