ion, ion- +

(Greek: ion, "going"; neuter present participle of ienai, "to go"; because an ion moves toward the electrode of an opposite charge)

ionic semiconductor
1. A solid in which the electrical conductivity from the flow of ions predominates over that from the movement of electrons or holes.
2. A solid whose electrical conductivity is due primarily to the movement of ions rather than that of electrons and holes.
3. A semiconductor whose primary charge carriers are ions instead of electrons and holes.
ionic spectrum, spark spectrum
1. The spectrum produced by a spark discharging through a gas or vapor.

With metal electrodes, a spectrum of the metallic vapor is obtained.

ionic strength
The sum of the concentrations of all ions in a solution multiplied by the square of their charge.
ionic strength principle
The concept that the amount of ionic activity in an electrolytic solution is based on the charge on the ions present rather than on their particular chemical natures.
ionic tweeter
A type of speaker in which a varying electrostatic field activates a mass of air ionized by a high-voltage radio-frequency field.

Ionic speakers are capable of extremely extended high-frequency response (up to 100 kHz or so) because of the extreme lightness of the ionic "diaphragm".

ionic-heated cathode, ionic heated cathode
A hot cathode heated primarily by ionic bombardment of the emitting surface.
1. The ionic characteristics of a solid.
2. Relating to, existing as, or characterized by ions (ionic gases, the ionic charge).
3. Based on or functioning by means of ions.
A naturally occurring radioactive isotope of the chemical element thorium.
1. The process of adding an electron to, or removing an electron from, an atom or molecule so as to give a negative or positive net charge.

The atom is then called an ion.

2. A process in which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions) by the removal or addition of negatively charged electrons.

It is one of the principal ways in which radiation transfers energy to matter, and hence of detecting radiation.

In general, ionization occurs whenever sufficiently energetic charged particles or radiant energy travels through gases, liquids, or solids.

A certain minimal level of ionization is present in the earth's atmosphere because of continuous absorption of cosmic rays from space and ultraviolet radiation from the sun.

3. The process by which a neutral atom, or a cluster of such atoms, becomes an ion.

This may occur, for instance, by absorption of light ("photoionization") or by a collision with a fast particle ("impact ionization").

Also, certain molecules (such as table salt or sodium chloride, NaCl) are formed by natural ions (like Na+ and Cl-) held together by their electric attraction, and they may fall apart when dissolved in water (which weakens the attraction), enabling the solution to conduct electricity.

4. Production of charged atoms or molecules in a gas by electric discharge or by irradiation.
ionization arc-over
1. Arcing across terminals or contacts due to ionization of the adjacent air or gas.
2. Arcing across satellite antenna terminals as the satellite passes through the ionized regions of the ionosphere.
3. An electric spark which is created when ionized charges build up in a medium and produce forces on the electrons.
ionization chamber
1. A device that measures the intensity of ionizing radiation.
2. A device used to detect and measure ionizing radiation, consisting of a gas-filled tube with electrodes at each end between which a voltage is maintained.

Radiation that ionizes gas molecules in the tube causes a current between the electrodes, the strength of which is a function of the radiation's intensity.

3. A gas-filled enclosure fitted with electrodes between which electric current flows upon ionization of the gas by incident radiation, the electrodes being maintained at a potential difference just sufficient to collect ions thus produced without causing further ionization.
4. The device for the detection and measurement of ionizing radiation.

It consists basically of a sealed chamber containing a gas and two electrodes between which a voltage is maintained by an external circuit.

When ionizing radiation; such as, a photon, enters the chamber (through a foil-covered window), it ionizes one or more gas molecules.

The ions are attracted to the oppositely charged electrodes; their presence causes a momentary drop in the voltage, which is recorded by the external circuit.

The observed voltage drop helps identify the radiation because it depends on the degree of ionization, which in turn depends on the charge, mass, and speed of the photon.

Geiger-Müller counter

A Geiger-Müller counter results from the application of a still-higher voltage across the electrodes of a proportional counter.

Individual particles of various kinds and energies entering a Geiger-Müller counter produce essentially the same large output pulse, making the instrument an excellent counter of individual particles.

The mixture of gases within a Geiger counter quenches the avalanche of ions produced by a single particle of radiation so that the device can recover to detect another particle.

An additional significant increase in voltage causes a continuous current to flow through the gas between the electrodes, rendering the device useless for detecting radiation.

—Compiled from "ionization chamber", Encyclopædia Britannica; 2010;
Encyclopædia Britannica Online; May 22, 2010.
ionization coefficient, specific ionization
The number of ion pairs formed per unit distance along the track of an ion passing through matter.
ionization constant
1. Analog of the dissociation constant; used for the application of the law of mass action to ionization.
2. An equilibrium constant for the ionization of a weak electrolyte.
3. A constant that depends upon the equilibrium between the ions and the molecules that are not ionized in a solution or liquid.
ionization cross section
1. The cross section for a particle or photon to undergo a collision with an atom, and so removing or adding one or more electrons to the atom.
2. An area in which the probability that an atom or ion will undergo ionization when it collides with a particle or photon of sufficient energy is measured.
ionization current, gas current
1. A current produced in an ionized gas by an electric field.
2. A positive-ion current produced by collisions between electrons and residual gas molecules in an electron tube.

A cross reference of word units that are related, directly and/or indirectly, with "electricity": electro-; galvano-; hodo-; piezo-; -tron; volt; biomechatronics, info; mechatronics, info.