Irradiation

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Irradiation is the process by which an item is exposed to radiation. The exposure can be intentional, sometimes to serve a specific purpose, or it can be accidental. In common usage the term refers specifically to ionizing radiation, and to a level of radiation that will serve that specific purpose, rather than radiation exposure to normal levels of background radiation or abnormal levels of radiation due to accidental exposure.

[edit] Explanation

Most forms of radiation do not induce a state of radioactivity in the target. Examples of this include gamma rays, electron beams or X-rays if employed at or below the energy levels permitted by national and international regulatory agencies for industrial applications. Gamma rays and X-rays are very-short-wavelength electromagnetic radiation consisting of photons that penetrate through solid matter until they scatter electrons from molecules by means of the compton effect or at lower levels the photoelectric effect. These electrons then induce the desired effects in the material, by destroying pathogen DNA or improving material characteristics. Electron beam irradiation employs electrons, but has a much lower power of penetration.

[edit] Applications

If administered at appropriate levels, all of these forms of radiation can be used to sterilize objects, a technique used in the production of medical instruments and disposables, such as syringes as well as in the disinfestation and sterilization of food. Irradiation can further more be used in cross-polymerization of plastics or to improve material qualities of semi-precious stones. Irradiation is also employed to prevent sprouting of certain cereals, onions, potatoes and garlic. During the 2001 anthrax attacks, the US Postal Service irradiated mail to protect members of the US government and other possible targets. This can be of some concern to people, including artists; according to the ART in Embassies programme "incoming mail is irradiated, and the process destroys slides, transparencies and disks."[1]