-tron, -tronic, -tronics +

(Greek: a suffix referring to a device, tool, or instrument; more generally, used in the names of any kind of chamber or apparatus used in experiments)

A possible allusion to the Greek instrumental suffix, as in árotron, "plow" as spelled in the U.S. or "plough", as spelled by the British; from the Greek stem aroun, "to plow".

The suffix -tron is the result of the combining form extracted from electron, used with nouns or combining forms, principally in the names of electron tubes (ignitron; klystron; magnetron) and of devices for accelerating subatomic particles (cosmotron; cyclotron); also, more generally, in the names of any kind of chamber or apparatus used in experiments (biotron).

electron diffractograph (s) (noun), electron diffractographs (pl)
1. A device which produces an electron-diffraction pattern by focusing an electron beam onto a crystal specimen, allowing the user to examine the crystal structure of the sample.
2. An instrument related to the electron microscope, in which a beam of electrons strikes the sample, showing crystal pattern and other physical attributes on the resulting diffraction pattern: An electron diffractograph is used for chemical analysis, atomic structure determination, etc.
electron distribution
1. An action that describes the electron density in phase space (a spectral representation of physical space).
2. A function that produces the number of electrons per unit volume of phase space.
electron donor
1. An electron donor in an oxidation-reduction (redox) reaction or a molecule or compound that gives up electrons in an oxidation-reduction reaction in which electrons are removed from one molecule or atom and given to another molecule or atom.
2. A chemical element that donates electrons to another compound.

It is a reducing agent which, because of its donating electrons, is itself oxidized in the process.

electron emission
1. The release of electrons from a specific material into the surrounding area or space.

It may be caused by an electric field, light, heat, or impact chemical disintegration.

2. A liberation of electrons from a substance into a vacuum.

Since all substances consist of atoms and since all atoms contain electrons, any substance may emit electrons; usually, however, the term refers to the emission of electrons from the surface of a solid.

3. The freeing of electrons into space from the surface of a body under the influence of heat, light, impact, chemical disintegration, or a potential difference.
electron emitter
1. A material from which electrons are released or an electrode from which electrons are emitted.
2. In a cathode tube, the electrode which serves as a source for electrons.
electron energy level
1. The quantum-mechanical representation of the energy level of an electron in an atom, which determines the orbit of the electron around the nucleus.
2. A quantum-mechanical concept for energy levels of electrons around the nucleus.

Electron energies are functions of each particular atomic species.

electron flow
1. The movement of electrons through a metal or other conductive material from a negative to a positive point, or from a negative to a positive electrode through a liquid, a gas, or a vacuum.
2. A current produced by the motion of free electrons toward a positive terminal.

The direction of electron flow is opposite to that of the current.

electron gun
1. A device, within an electron tube or cathode-ray tube, that produces an electron beam and which directs its movement.
2. A device that directs a steady stream of electrons in a desired direction; for example, in a cathode-ray tube.

Electron guns are also used in oil refining and various other industries.

3. An electrode structure that produces and may control, focus, and deflect a beam of electrons; such as, in a television picture tube, where the beam produces a visual pattern on the tube's screen.

The source of the electron beam is the cathode, a flat metal support covered with oxides of barium and strontium.

When they are heated by a coil behind the support, these oxides produce electrons, that are drawn toward a positively charged sleeve (first anode) which is contoured to allow the electron beam to flow within the inside diameter.

The beam is then electrostatically constricted and collimated by a metal disk with a hole (the

—Compiled from "electron gun", Encyclopædia Britannica; 2010;
Encyclopædia Britannica Online; June 7, 2010.
electron hole
1. A vacant position in a crystal left by the absence of an electron; especially, a position in a semiconductor that acts as a carrier of positive electric charges.
2. In a semiconductor, the electron vacancy in the valence (combining power of atoms) band that occurs when an electron jumps the gap from the filled valence band to the empty conduction band.

It serves as a positive charge carrier, allowing electrons deeper in the band to move into the vacated area.

A valence is the combining power of atoms or groups measured by the number of electrons the atom or group will receive, give up, or share in forming a compound.

electron microscope
1. A device which uses electrons, generally focused by electron lenses, to magnify tiny objects onto a fluorescent screen or photographic plate.

It provides much greater plowers of magnification than an optical microscope; that is, up to 1,000,000 times actual size without loss of sharpness and degree of contrast in the image.

2. An electronic instrument that scans cell and tissue sections with a beam of electrons instead of visible light.

The specimen is stained with electron-opaque dyes and with its high magnification power, it creates an image that can be photographed or viewed on a florescent screen.

3. A device for directing streams of electrons by means of electric and magnetic fields in a manner similar to the direction of visible light rays by means of glass lenses in an ordinary microscope.

Since electrons carry waves of much smaller wavelengths than light waves, correspondingly greater magnifications can be obtained.

The electron microscope will resolve details from 1,000 to 10,000 times finer than the optical microscope and images can be studied on a fluorescent screen or recorded photographically.

electron scanning microscope, scanning electron microscope, SEM
An instrument similar to an electron microscope in that a beam of electrons is used to scan the surface of a specimen.

The beam is moved in a point-to-point manner over the surface of the specimen and these electrons are deflected collected, accelerated, and directed against a scintillator.

The large number of photons that are created are converted into an electric signal which, in turn, modulates the beam scanning the surface of the specimen.

electron shell
1. The collection of all the electron states in an atom which have a given principal quantum number and a given orbital angular momentum quantum number.
2. The arrangement of electrons at various distances from the nucleus of an atom, according to the energy that they have.

Those with the least energy are in the shell closest to the nucleus, traditionally called the K shell, which can hold no more than two electrons.

The Q shell, farthest from the nucleus, can hold 98 electrons, but it is never completely filled.

electron tube, electron valve
1. An instrument in which electrons move through a vacuum or gaseous medium within a gas-tight chamber; used to generate, to amplify, and to correct electric oscillations and AC currents.
2. An electronic apparatus that consists, typically, of a sealed glass bulb containing two or more electrodes.

It is used to generate, to amplify, and to rectify electric oscillations and alternating currents.

3. An electron device in which electricity is conducted by electrons moving through a vacuum or gaseous medium within an hermetically sealed envelope.

A tube can perform rectification, amplification, modulation, demodulation, oscillation, limiting, and a variety of other activities.

Examples include cathode-ray tubes, gas tubes, phototubes, and vacuum tubes.

electron volt, electronvolt, eV
1. A unit of energy equal to the energy acquired by an electron falling through a potential difference of one volt.
2. A unit of energy defined as the kinetic energy acquired by an electron that is accelerated through a potential difference of one volt; equivalent to 1.6022 x 10-19 joules.
3. A unit of energy used in atomic and nuclear physics, equal to the energy gained by an electron.
4. A unit of electrical energy used in nuclear physics.

It is equal to the energy gained by an electron when it moves from one point to a point higher in potential by one volt and it is a unit of energy or work, not of voltage.

electron-beam drilling, electron beam drilling
1. The process of boring tiny holes into a material; such as, a ferrite or semiconductor, with a tightly focused electron beam.
2. Drilling of tiny holes in a ferrite, semiconductor, or other material by using a sharply focused electron beam to melt and evaporate or sublimate the material in a vacuum.