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Encyclopedia > Alpha decay
Nuclear processes

Alpha decay

${}^2{}^{38}_{92}hbox{U};to;{}^2{}^{34}_{90}hbox{Th};+;{}^4_2hbox{He}^{2+},$

although this is typically written as:

${}^{238}hbox{U};to;^{234}hbox{Th};+;alpha.$

(The second form is preferred because the first form appears electrically unbalanced. Fundamentally, the recoiling nucleus is very quickly stripped of two electrons to neutralize the ionized helium cation.)

An alpha particle is identical to a helium nucleus, and both mass number and atomic number are the same. Alpha decay is a form of nuclear fission where the parent atom splits into two daughter products. Alpha decay is fundamentally a quantum tunneling process. Unlike beta decay, alpha decay is governed by the strong nuclear force. An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... For the generation of electrical power by fission, see Nuclear power plant An induced nuclear fission event. ... Quantum tunneling is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... The strong nuclear force or strong interaction (also called color force or colour force) is a fundamental force of nature which affects only quarks and antiquarks, and is mediated by gluons in a similar fashion to how the electromagnetic force is mediated by photons. ...

Alpha particles have a typical kinetic energy of 5 MeV (that is ≈0.13% of their total energy, i.e. 110 TJ/kg) and a speed of 15,000 km/s. This corresponds to a speed of around 0.05c. Because of their relatively large mass, +2 charge and relatively low velocity, they are very likely to interact with other atoms and lose their energy, so they are effectively absorbed within a few centimeters of air.

Opened Alphachamber

Most of the helium produced on Earth comes from the alpha decay of underground deposits of minerals containing uranium or thorium. The helium is brought to the surface as a by-product of natural gas production. Image File history File links Size of this preview: 799 Ã— 599 pixelsFull resolution (845 Ã— 634 pixel, file size: 80 KB, MIME type: image/jpeg) Author: Michael A. Zapletal, Austria http://de. ... Image File history File links Size of this preview: 799 Ã— 599 pixelsFull resolution (845 Ã— 634 pixel, file size: 80 KB, MIME type: image/jpeg) Author: Michael A. Zapletal, Austria http://de. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... Minerals are natural compounds formed through geological processes. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass 232. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Natural gas is a gaseous fossil fuel consisting primarily of methane but including significant quantities of ethane, butane, propane, carbon dioxide, nitrogen, helium and hydrogen sulfide. ...

By 1928, George Gamow had solved the theory of the alpha decay via tunneling. The alpha particle is trapped in a potential well by the nucleus. Classically, it is forbidden to escape, but according to the then newly discovered principles of Quantum mechanics, it has a tiny (but non-zero) probability of "tunneling" through the barrier and appearing on the other side to escape the nucleus. Year 1928 (MCMXXVIII) was a leap year starting on Sunday (link will display full calendar). ... George Gamow (pronounced GAM-off) (March 4, 1904 â€“ August 19, 1968) , born Georgiy Antonovich Gamov (Ð“ÐµÐ¾Ñ€Ð³Ð¸Ð¹ ÐÐ½Ñ‚Ð¾Ð½Ð¾Ð²Ð¸Ñ‡ Ð“Ð°Ð¼Ð¾Ð²) was a Ukrainian born physicist and cosmologist. ... Fig. ...

## Toxicity

As any heavy charged particle, alpha particles lose their energy within a very short distance in dense media, causing significant damage to surrounding biomolecules. Generally, external alpha irradiation is not harmful because alpha particles are completely absorbed by the thin layer of dead skin cells in the outermost layer of the skin as well as by a few centimeters of air. However, if a substance radiating alpha particles is ingested, inhaled by, injected into, or introduced through the skin (shrapnel, corrosive chemicals) into an organism it may become a risk, potentially inflicting very serious cellular damage. In zootomy and dermatology, skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs. ...

A common household source of alpha radiation is americum 241. It is used in smoke detectors which use the radiation to test for smoke. Radon is a naturally occurring, radioactive gas found in soil, rock and sometimes groundwater. When radon gas is inhaled, some of the radon particles stick to the inner lining of the lung. The particles that remain continue to decay over time, emitting alpha particles which may damage cells in the lung tissue.[1] Shrapnel deposited in the body from depleted uranium poses another such internal risk of alpha particle radiation dose. General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) gÂ·molâˆ’1 Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Density (0 Â°C, 101. ...

The death of Marie Curie at age 66 from leukemia, was likely caused from radiation exposure, such as alpha particles from radium, during her years of important research on the subject. Madame Curie redirects here. ...

The 2006 assassination of Russian dissident Alexander Litvinenko is thought to have been caused by poisoning with polonium-210, an active alpha emitter. Alexander Valterovich Litvinenko (Russian: ) (30 August 1962[1][2] â€“ 23 November 2006) was a lieutenant-colonel in the Federal Security Service of the Russian Federation and later a Russian dissident and writer. ... Polonium-210 is the most readily available isotope of Polonium. ...

Results from FactBites:

 Alpha decay - Wikipedia, the free encyclopedia (306 words) Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle through the electromagnetic force and transforms into a nucleus with mass number 4 less and atomic number 2 less. Alpha decay can essentially be thought of as nuclear fission where the parent nucleus splits into two daughter nuclei. Alpha decay is fundamentally a quantum tunneling process.
 Alpha particle - Wikipedia, the free encyclopedia (885 words) Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. In contrast to beta decay, alpha decay is mediated by the strong nuclear force. When an alpha particle is emitted, the atomic mass of an element goes down by roughly 4 amu, due to the loss of 4 nucleons.
More results at FactBites »

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