Saturday, March 27, 2010

RAIDITION

In physics, radiation describes any process in which energy travels through a medium or through space, ultimately to be absorbed by another body. Non-physicists often associate the word with ionizing radiation (e.g., as occurring in nuclear weapons, nuclear reactors, and radioactive substances), but it can also refer to electromagnetic radiation (i.e., radio waves, infrared light, visible light, ultraviolet light, and X-rays) which can also be ionizing radiation, to acoustic radiation, or to other more obscure processes. What makes it radiation is that the energy radiates (i.e., it travels outward in straight lines in all directions) from the source. This geometry naturally leads to a system of measurements and physical units that are equally applicable to all types of radiation. Some radiations can be hazardous.

THE DIFFERENT TYPES OF RAIDIATIONS
Alpha radiation

Alpha (α) decay is a method of decay in large nuclei. An alpha particle (helium nucleus, He2+), consisting of 2 neutrons and 2 protons, is emitted. Because of the particle's relatively high charge, it is heavily ionizing and will cause severe damage if ingested. However, due to the high mass of the particle, it has little energy and a low range; typically alpha particles can be stopped with a sheet of paper (or skin).




Beta(+/-) radiation

Beta-minus (β-) radiation consists of an energetic electron. It is less ionizing than alpha radiation, but more than gamma. The electrons can often be stopped with a few centimeters of metal. It occurs when a neutron decays into a proton in a nucleus, releasing the beta particle and an antineutrino.

Beta-plus (β+) radiation is the emission of positrons. Because these are antimatter particles, they annihilate any matter nearby, releasing gamma photons.

Gamma radiation

Gamma (γ) radiation consists of photons with a frequency of greater than 1019 Hz[1]. Gamma radiation occurs to rid the decaying nucleus of excess energy after it has emitted either alpha or beta radiation.

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