electro-, electr-, electri-

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.

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.

An electrostatic apparatus which uses an electric potential barrier to allow the transmission of electrons at or above a set level of energy while stopping the passage of those electrons below that set level of energy.

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.

1. The total energy per unit area carried by a pulse of electromagnetic radiation.
2. A measure of time-integrated particle flux, expressed in particles per square centimeter.

It is used for electrons in electron irradiation and for neutrons in connection with the effects of nuclear radiation on electronic components.

Any system of free electrons.

Each electron goes to form the communal "electron gas" which is responsible for the high electrical and thermal conductivity of the metallic state.

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

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.

1. A pattern of electric charges on an insulating plate, with the magnitude of the charge at each point being proportional to the brightness of the corresponding point in an optical image.
2. A representation of an object formed by a beam of electrons focused by an electron optical system.
3. An image formed in a stream of electrons.

The electron density in a cross section of the stream is at each point proportional to the brightness of the corresponding point in an optical image.

1. A tool which projects an optical image generated by electromagnetic radiation from a photosensitive surface onto a fluorescent screen.
2. An electron tube which reproduces on its fluorescent screen an image of the optical image or other irradiation pattern arriving at or striking its photosensitive surface.
3. A cathode-ray tube that has a photoemissive mosaic upon which an optical image is projected, and an electron gun to scan the mosaic and to convert the optical image into a corresponding electrical current.

1. The release of electrons from one solid material into another solid material.
2. The emission of electrons from one solid into another solid.
3. The process of injecting a beam of electrons with an electron gun into the vacuum chamber of a mass spectrometer, betatron, or other large electron accelerator.
4. The procedure used in forcing a beam of electrons into any large electron accelerator; such as, a beatatron by using an electron gun.

An electron gun which injects a beam of electrons into the vacuum chamber of a mass spectrometer, betatron (type of particle accelerator for producing high-energy beams of electrons), or other large electron accelerator.

1. Electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons.
2. An electric or magnetic field, or a combination of such, that acts upon an electron beam in a manner similar to that in which an optical lens acts upon a light beam.
3. A tool which uses an electromagnetic field to refract an electron beam in a manner similar to the refraction of light by an optical lens.
4. A system of deflecting electrodes or coils designed to produce an electric field which influences a beam of electrons in the same manner that a lens affects a light beam.
5. An electric field used to focus a stream of electrons on a target.

The number of very small particles and associated neutrinos minus the number of positrons and associated antineutrinos: As an engineer, Mildred made a careful study of the electron lepton numbers during her analysis of colliding atoms in the air, noting that they were generating more electrons as well as x-rays and gamma rays.

A linear accelerator or a device that propels charged particles in straight paths by using alternating high-frequency voltages used to accelerate electrons in a straight line, usually by means of radio-frequency fields which are produced in a loaded waveguide and travel with the electrons.