alpha particle


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alpha particle,

one of the three types of radiation resulting from natural radioactivityradioactivity,
spontaneous disintegration or decay of the nucleus of an atom by emission of particles, usually accompanied by electromagnetic radiation. The energy produced by radioactivity has important military and industrial applications.
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. Alpha radiation (or alpha rays) was distinguished and named by E. R. Rutherford in 1909, who found by measuring the charge and mass of alpha particles that they are the nuclei of ordinary helium atoms. Alpha particles consist of two protons and two neutrons (see nucleusnucleus,
in physics, the extremely dense central core of an atom. The Nature of the Nucleus
Composition

Atomic nuclei are composed of two types of particles, protons and neutrons, which are collectively known as nucleons.
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).

alpha particle

(α particle) The nucleus of a helium atom, i.e. a positively charged particle consisting of two protons and two neutrons. It is thus a fully ionized helium atom. Alpha particles are very stable. They are often ejected in nuclear reactions, including alpha decay in which a parent nucleus disintegrates – or breaks up – into an alpha particle and a lighter daughter nucleus.

alpha particle

[′al·fə ‚pärd·ə·kəl]
(atomic physics)
A positively charged particle consisting of two protons and two neutrons, identical with the nucleus of the helium atom; emitted by several radioactive substances.

alpha particle

a helium-4 nucleus, containing two neutrons and two protons, emitted during some radioactive transformations

alpha particle

References in periodicals archive ?
Because a person's exposure to alpha particles typically is low, researchers have had to estimate public health threats from radon by extrapolating from the effects of higher doses of alpha radiation.
The aim, essentially, is to start from oxygen gas and split its nucleus into its starting ingredients: an alpha particle and a carbon-12 nucleus.
Earlier, on the basis of this model the binding energy of the deuteron, triton and alpha particle have been determined [2], as well as many other parameters for both micro- and macrocosm [3-6].
Mann, Backscattering of alpha particles from thick metal backings as a function of atomic weights, Int.
As it can be seen in the radon decay chain, number of alpha particles emitted in this chain is high and given that alpha particle considered as one of the most dangerous particles resulted from decays so this gas can be considered as one of the dangerous radioactive gases.
Caption: Euriosity's two-metre-long robotic arm contains a variety of tools including cameras, a drill, a soil scoop and an alpha particle X-ray spectrophotometer (APXS), visible here as a can-shaped device located at the 10 o'clock position.
Low-level exposure to [.sup.210]Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic and fetal tissues where exposure to a single alpha particle may kill or damage critical cells.
As a result of the recent UCT/AIT merger, increased level of vertical integration will enable UCT to design, engineer and manufacture the UltraLo-1800 alpha particle counter more efficiently and with a shorter cycle time.
That is why the efficiency of alpha particle interaction with the wave increases, and the growth rates become greater than that of the case [DELTA] = 0.1.
No number of small deflections by the gold atoms' internal electric charges could have diverted an alpha particle's path so dramatically, he determined, applying some statistical probability calculations (he had once audited statistics classes to prepare himself to deal with such issues).
Radon is a naturally occurring radioactive alpha particle emitting colorless, odorless and tasteless gas produced by radioactive decay of uranium and thorium.
Three of the 11 papers in this collection present research from the City University of Hong Kong on using solid state nuclear track detectors to measure radon progeny concentrations, as substrates for alpha particle radiobiologic experiments, and to study the optical characteristics of etched tracks.