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 ?
Indeed, for the emitted alpha particles there are two energy ranges: with the upper limit of 2-4 MeV for rare earth elements and 4-9 MeV for the elements heavier than lead [11].
210]Po through the digestive tract may increase sharply (Moroz and Parfenov 1972), possibly because of damage to the intestinal wall through persistent bombardment by alpha particles.
That is, as the radiation source becomes more distributed--by deformation, by fragmentation, or by dispersion amid the soft tissue--the number of cells within range of the alpha particles increases.
Weller found that since the boron fusion process produces twice as many alpha particles moving at high speed, and thus would produce twice the energy.
iRoC Technologies provides a wide spectrum of simulation, testing and measurement capabilities related to medium and high energy particles associated with neutrons and alpha particles induced errors in semiconductor designs.
Leading ASIC Supplier Continues Strategy to Proactively Measure Soft Error Impacts of Atmospheric Neutron and Alpha Particles to Assure Reliability
For example, uranium-238 (element number 92), which is used in nuclear reactors, loses an alpha particle to become thorium-234 (element number 90).
The data indicate that if the age of a disk and average temperature of a home were known, measurements of alpha particle etching in a compact disk could indicate radiation exposure from radon with an accuracy of about 10 percent, Pressyanov and his team claim.
The purpose of the contract is to replace the existing van de Grff accelerator by a tandem accelerator, delivering proton, deuteron and alpha particle beams with similar characteristics as those from the present machine.
After a short drive the preceding day to get within arm's reach of the football-size rock, Curiosity put its Alpha Particle X-Ray Spectrometer (APXS) instrument in contact with the rock during the rover's 46th Martian day, or sol.
Will a high density of energetic alpha particles destabilize waves and degrade alpha confinement so as to reduce the efficiency of alpha particle heating?
Checkouts in the next several days will include using the turret's Mars Hand Lens Imager to observe its calibration target and the Canadian-built Alpha Particle X-Ray Spectrometer to read what chemical elements are present in the instrument's calibration target.