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spallation
spallation A type of nuclear fission that takes place when matter is bombarded by high‐energy atomic particles or cosmic rays. Meteoroids, asteroids, and the Moon are all bombarded by solar particles and cosmic rays, chiefly very high‐energy protons. These interact with elements in their surface rocks, producing atoms such as helium‐3, neon‐21, and argon‐38. Spallation also changes the overall composition of high‐energy galactic cosmic rays when they collide with stationary atoms of interstellar matter. New atoms of light elements such as lithium, boron, and beryllium are produced. Consequently, these elements are a million times more abundant in cosmic rays than in stars.
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"spallation." A Dictionary of Astronomy. 1997. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. "spallation." A Dictionary of Astronomy. 1997. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O80-spallation.html "spallation." A Dictionary of Astronomy. 1997. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-spallation.html |
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spallation
spallation
1. (nuclear) A nuclear reaction involving the ejection of many particles from an atomic nucleus, following a collision with a high-energy particle. Both the mass number and the atomic number of the target nucleus are changed by the event. 2. (planetary geol.) The removal of the surface layers of a rock by the interaction of a compressional shock wave with the surface, caused by micrometeorite impact. See ‘ZAP PITS’. |
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AILSA ALLABY and MICHAEL ALLABY. "spallation." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "spallation." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O13-spallation.html AILSA ALLABY and MICHAEL ALLABY. "spallation." A Dictionary of Earth Sciences. 1999. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-spallation.html |
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