ion, ion- +
(Greek: ion, "going"; neuter present participle of ienai, "to go"; because an ion moves toward the electrode of an opposite charge)
2. The visible train of ionized gas left by a meteorite entering the atmosphere.
2. The number of ions per unit volume.
3. The density of ions in a gas.
2. An apparatus that counts the number of unit charges of electricity that are contained in a sampled volume of the atmosphere.
The general procedure is to pass a sample of the atmosphere through a charged cylindrical condenser.
The change in the potential across the condenser is a measure of the ionic charge contained in the sample volume and the change in potential depends upon such factors as the polarizing potential of the condenser, the mobility and charge of the ions, volume and length of the condenser, and sample flow rate.
2. The electric current resulting from the motion of ions.
2. An engine that provides thrust by expelling accelerated or high-velocity ions.
Ion engines using energy provided by nuclear reactors are proposed for space vehicles.3. A type of rocket engine that generates thrust from the electrostatic acceleration of ionized particles.
2. The use of such a process to replace certain selected anions or cations in a solution; for example, to remove undesirable substances, as in water softening, or to recover desirable ones, as in the separation of valuable metals from wastes.
3. The interchange of ions of the same charge between a solution and a solid in contact with it.
4. A reversible chemical reaction between an insoluble solid and a solution during which ions may be interchanged, used in water softening and in the separation of radioactive isotopes.
5. A chemical reaction in which mobile hydrated ions of a solid are exchanged, equivalent for equivalent, for ions of like charge in solution.
The solid has an open, fish-net-like structure, and the mobile ions neutralize the charged, or potentially charged, groups attached to the solid matrix.
The solid matrix is termed the ion exchanger.
2. A device; such as, a Geiger counter, that determines the amount of radiation in a medium by measuring the ionization generated by charged particles passing through a gaseous substance.
2. A method of implanting impurities below the surface of a solid, usually a semiconductor, by bombarding the solid with a beam of ions of the impurity.
3. A process that utilizes accelerated ions to penetrate a solid surface.
The implanted ions can be used to modify the surface composition, structure, or property of the solid material.
Ion implantation is used extensively in the semiconductor industry and the fabrication of integrated circuits in silicon often requires many steps of ion implantation with different ion species and energies.
Ion implantation is also used to change the surface properties of metals and alloys. It has been applied successfully to improve wear resistance, fatigue life, corrosion protection, and chemical resistance of different materials.
2. A spectrometric technique that uses a beam of ions of high kinetic energy passing through a field-free reaction chamber from which ionic products are collected and energy analyzed.
It is a generalization of metastable ion studies in which both uni-molecular and bi-molecular reactions are investigated.
2. A gas laser in which stimulated emission takes place between two energy levels of an ion.
Gases used include argon, krypton, neon, and xenon; examples include helium-cadmium lasers and metal vapor lasers.
2. Use of a high-velocity ion beam to remove material from a surface.