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[spaw-ley-shuh n] /spɔˈleɪ ʃən/
noun, Physics.
a nuclear reaction in which several nucleons are released from the nucleus of an atom.
1945-50; spall + -ation Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for spallation
  • The new mission calls for the development and use of spallation neutron sources for research and applications.
  • In this case the system is driven by a proton accelerator that provides the additional neutrons via the spallation process.
British Dictionary definitions for spallation


(physics) a type of nuclear reaction in which a photon or particle hits a nucleus and causes it to emit many other particles or photons
Word Origin
C20: from spall + -ation
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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spallation in Medicine

spallation spal·la·tion (spô-lā'shən)

  1. A nuclear reaction in which nuclei are bombarded by high-energy particles, causing the liberation of protons and alpha particles.

  2. Fragmentation.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Article for spallation

high-energy nuclear reaction in which a target nucleus struck by an incident (bombarding) particle of energy greater than about 50 million electron volts (MeV) ejects numerous lighter particles and becomes a product nucleus correspondingly lighter than the original nucleus. The light ejected particles may be neutrons, protons, or various composite particles equivalent to nuclei of hydrogen, helium, or lithium isotopes. The product nucleus is occasionally much lighter than the target nucleus; chlorine-38, for example, has been produced along with an assortment of neutrons, protons, and alpha particles (helium nuclei) by bombarding copper-63 with protons accelerated to 70 MeV.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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