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alpha decay

   Also found in: Dictionary/thesaurus, Wikipedia, Hutchinson 0.02 sec.

alpha decay

Type of radioactive disintegration (see radioactivity) in which some unstable atomic nuclei dissipate excess energy by spontaneously ejecting an alpha particle. Alpha particles have two positive charges and a mass of four atomic mass units; they are identical to helium nuclei. Though they are emitted at speeds about one-tenth that of light, they are not very penetrating and have ranges in air of about 1–4 in. (2.5–10 cm). Alpha decay commonly occurs in elements with atomic numbers greater than 83 (bismuth), but can occur in some rare-earth elements in the atomic-number range of 60 (neodymium) to 71 (lutetium). Alpha decay half-lives range from about a microsecond (10−6 second) to billions of years (1017 seconds).


alpha decay [′al·fə di′kā]
(nuclear physics)
A radioactive transformation in which an alpha particle is emitted by a nuclide.


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Their blood level initially decays relatively rapidly, representing the alpha decay period (Flesch-Janys et al.
During a routine check for contamination in their bolometers, which happen to be built around crystals containing bismuth, the team noticed an unexpected alpha decay not listed in any reference tables.
Some of the unique VIPER(TM) algorithms available through EARN(TM) include VIEESP, a statistical prediction algorithm which employs a short-term, predictive model that formulates expectations of the price and volume of a stock in the next one to three minutes, and INLINE, a mode which works best for stocks with high alpha decay, that participates at a higher percentage of non-block volume by being less patient for strong trade signals.
 
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