| electron cyclotron emission | <physics, radiobiology> As electrons gyrate around in a magnetic field (see also larmor radius or cyclotron radius), they radiate radio-frequency electromagnetic waves. This is known as electron cyclotron emission, and can be measured to help diagnose a plasma. (09 Oct 1997) |
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| electron cyclotron heating | <physics, radiobiology> Radiofrequency heating scheme that works by injecting electromagnetic wave energy at the electron cyclotron gyration frequency. The electric field of the electromagnetic wave at this frequency looks to a gyrating electron like a static electric field, and thus causes large acceleration of the electron (larger than if the frequency were off the cyclotron frequency and thus, to the electron, appearing to change direction as a function of time). The accelerated electron gains energy, which is then shared with other particles through collisions, resulting in heating. Higher harmonics (multiples) of the cyclotron frequency can also be used in principle. (09 Oct 1997) |
| electron diffraction | <technique> The phenomenon, or technique of producing diffraction patterns through the incidence of electrons upon matter. (05 Aug 1998) |
| electron donor | A molecule or compound that gives up electrons in an oxidation-reduction reaction. (09 Oct 1997) |
| electron gun | <apparatus> A cathode/anode device intended to produce a stream of electrons. Also used inside a video camera tube and monitor picture tube that contains a heated cathode. Electrons emitted by the gun are focused to produce the scanning beam. (05 Aug 1998) |
| electron image | <microscopy> A representation of an object formed by a beam of electrons focused by an electron optical system. (05 Aug 1998) |
| electron interferometer | An interferometer that employs an electron beam in place of a light beam. (05 Mar 2000) |
| electron interferometry | Interferometry in which a beam of electrons is used instead of a beam of light. (05 Mar 2000) |
| electron lens | <physics> A device for focusing an electron beam. (05 Aug 1998) |
| electron magneton | bohr magneton |
| electron micrograph | <microscopy> A photographic reproduction of an image formed by the action of an electron beam. Electron microscope See: microscope, electron. (05 Aug 1998) |
| electron microprobe | A technique of elemental analysis in the electron microscope based on spectral analysis of the scattered X-ray emission from the specimen induced by the electron beam. Using this technique it is possible to obtain quantitative data on, for example: the calcium concentration in different parts of a cell, but it is necessary to use ultra thin frozen sections. (18 Nov 1997) |
| electron microscope | <instrument> A microscope (device used to magnify small objects) which beams electrons at and through the object of interest instead of light beams. Instead of a glass lens to bend the light, a powerful magnet is used to bend the electron beam. The microscope can only be operated in a vacuum. This type of microscope provides the greatest resolution of extremely small details available and has been used to see individual atoms in an object or substance. (09 Oct 1997) |
| electron microscopy | <procedure> Any form of microscopy in which the interactions of electrons with the specimens are used to provide information about the final structure of that specimen. In transmission electron microscopy the diffraction and adsorption of electrons as the electron beam passes normally through the specimen is imaged to provide information on the specimen. In scanning electron microscopy an electron beam falls at a nonnormal angle on the specimen and the image is derived from the scattered and reflected electrons. Secondary X-rays generated by the interaction of electrons with various elements in the specimen may be used for electron microprobe analysis. (18 Nov 1997) |
| electron optical axis | <physics> The path of an electron through an electron optical system along which it suffers no deflection due to lens fields. This axis does not necessarily coincide with the mechanical axis of the system. (05 Aug 1998) |