Electron Microscope

Definition: Electron Microscope

Electron Microscope

Noun

1. A microscope that is similar in purpose to a light microscope but achieves much greater resolving power by using a parallel beam of electrons to illuminate the object instead of a beam of light.

Specialty Definitions: Electron Microscope

Domain	Definitions
Electrical Engineering	Differs from the optical microscope in that it uses a beam of electrons instead of light rays. Source: European Union. (references)
Health	A microscope (device used to magnify small objects) that uses electrons (instead of light) to produce an enlarged image. An electron microscopes shows tiny details better than any other type of microscope. (references)
Source: compiled by the editor from various references; see credits.

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Specialty Definition: Electron microscope

(From Wikipedia, the free Encyclopedia)

The electron microscope can magnify very small details due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times.

History

The first electron microscope was built in 1931 by Ernst Ruska and Max Knoll. It was greatly developed through the 1950s and has allowed great advances in the natural sciences. The advantage of an electron beam is that it has a much smaller wavelength (see wave-particle duality), which allows a higher resolution - the measure of how close together two things can be before they are seen as one. Light microscopes allow a resolution of about 0.2 micrometres, whereas electron microscopes can have resolutions below 1 nanometer.

Process

Electron beams from a cathode are focused by magnetic lenses on to the specimen. They are then magnified by a series of magnetic lenses until they hit photographic plate or light sensitive sensors - which transfer the image to a computer screen. The image produced is called an electron micrograph (EM).

Types

The Transmission electron microscope (TEM) produces 2D images (for example of cellss) while the Scanning electron microscope (SEM) produces 3D images or models. As its name implies the TEM image is produced by detecting electrons that are transmitted through the sample. By contrast the SEM usually monitors secondary electrons which are emitted from the surface due to excitation by the primary electron beam. Generally, the TEM resolution is about an order of magnitude better than the SEM resolution, however, because the SEM image relies on surface processes rather than transmission it is able to image thicker samples and gives better 3D contrast.

Treatment

Samples viewed under an electron microscope have to be treated in many ways:

Fixation - is preserving the sample to make it more realistic. Glutaraldehyde - for hardening - and osmic acid - which stains lipids black - are used.
Dehydration - is the removing of water to be replaced with an embedding medium such as ethanol or propanone.
Embedding - supports the tissue for sectioning in a resin such as araldite.
Sectioning - produces thin slices for mounting. These can be cut on an ultramicrotome with a diamond knife to produce very thin slices.
Staining - uses metals such as lead and uranium to reflect electrons to give contrast between different structures.

Disadvantages

The samples have to be viewed in vacuums, as air would scatter the electrons. This means that no living material can be studied.
The samples have to be prepared in many ways to give proper detail resulting in artifacts - objects purely the result of treatment, and this gives the problem of distinguishing artifacts from biological material.

The man who scrutinized this aspect most thoroughly is Dr Harold Hillman from London. Like Ignaz Semmelweis he paid dearly for this heresy.

Electron microscopes are also very expensive to buy and maintain.

Wikipedia articles containing electron microscope images:

Ebola virus
Poliomyelitis

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Electron microscope."

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Crosswords: Electron Microscope

English words defined with "electron microscope": electron gun, electron microscopic ♦ field-emission microscope. (references)

Specialty definitions using "electron microscope": circuit board inspector, Corrosion Casting ♦ Electron Probe Microanalysis, electron-beam operator, energy dispersive spectroscopy, epicortex ♦ Freeze Etching, fusiform body ♦ GROUP LEADER, SEMICONDUCTOR PROCESSING ♦ INSPECTOR, PRINTED CIRCUIT BOARDS ♦ microfibril, Microscopy, Immunoelectron ♦ PHOTO MASK MAKER, ELECTRON-BEAM, production aide ♦ Replica Techniques ♦ structural petrology ♦ touch-up inspector, printed circuit boards ♦ WELDING-MACHINE OPERATOR, ELECTRON BEAM. (references)

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Commercial Usage: Electron Microscope

Domain	Title
Books	Computer Processing of Electron Microscope Images (Topics in Current Physics, Vol 13) (reference) Critical Issues in Scanning Electron Microscope Metrology: September-October 1994 (reference) Electron Diffraction in the Transmission Electron Microscope (Microscopy Handbooks) (reference) Electron Tomography: Three-Dimensional Imaging With the Transmission Electron Microscope (The Language of Science) (reference) Principles and Practice of Electron Microscope Operation (reference) (more book examples)
Source: compiled by the editor from various references; see credits.

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Photo Album: Electron Microscope

Thumbnail	Description & Credit
	The electron microscope - one of the wonders of modern technology. / WHO p.Credit: National Library of Medicine; photo by J. Mohr..
Source: compiled by the editor from various references; see credits.

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Non-Fiction Usage: Electron Microscope

Subject	Topic	Quote
Health		Scanning electron microscope study. (references)
		It was taken in an electron microscope. (references)
		Negatively stained Rhabdovirus as seen through an electron microscope. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

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Frequency of Internet Keywords: Electron Microscope

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day
electron microscope	113
scanning electron microscope	73
transmission electron microscope	27
electron microscope picture	15
electron microscope image	7
electron microscope scanning transmission	4
electron microscope siemens	4
history of the electron microscope	4
electron microscope photo	3
electron microscope tunneling	2
Source: compiled by the editor from various references; see credits.

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Modern Translations: Electron Microscope

Language		Translations for "electron microscope"; alternative meanings/domain in parentheses.
Czech		elektronový mikroskop. (various references)

Danish		elektronmikroskop (scanning electron microscope). (various references)

Dutch		elektronenmicroscoop. (various references)

French		microscope électronique. (various references)

German		elektronenmikroskop. (various references)

Greek		Ηλεκτρονικό μικροσκόπιο, ηλεκτρονικό μικροσκόπιο. (various references)

Italian		microscopio elettronico. (various references)

Japanese Kanji		電顕 , 電子顕微鏡 . (various references)

Japanese Katakana		で�"しけ�"びきょう, で�"け�". (various references)

Pig Latin		electronay icroscopemay.(various references)

Portuguese		microscópio electrónico. (various references)

Russian		электронный микроскоп. (various references)

Serbo-Croatian		elektronski mikroskop. (various references)

Spanish		microscopio electronico. (various references)

Vietnamese		kính hiển vi điện tử. (various references)
Source: compiled by the editor from various translation references.

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Misspellings: Electron Microscope

Misspellings
	"Electron Microscope" is suggested in spellcheckers for the following: electronmicroscope. (additional references)
Source: compiled by the editor, based on several corpora (additional references).

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Anagrams: Electron Microscope

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "c-c-c-e-e-e-i-l-m-n-o-o-o-p-r-r-s-t"
	-5 letters: isoproterenol, poltrooneries, scleroprotein.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.

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