• synonyms

slow neutron

noun Physics.
  1. a neutron with low kinetic energy, especially one slowed by the moderator in a nuclear reactor.
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Origin of slow neutron

First recorded in 1930–35
Also called thermal neutron.
Related formsslow-neu·tron, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for thermal neutrons

thermal neutrons

pl n
  1. slow neutrons that are approximately in thermal equilibrium with a moderator. They have a distribution of speeds similar to that of the molecules of a gas at the temperature of the moderator. Data concerning nuclear interactions are often given for standard thermal neutrons of speed 2200 metres per second, which is approximately the most probable speed at normal laboratory temperatures
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slow neutron

  1. physics a neutron having a kinetic energy of less than 100 electronvolts
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

thermal neutrons in Science

slow neutron

  1. A neutron that is in thermal equilibrium with the surrounding medium, especially one produced by fission in a nuclear reactor, and slowed by a moderator. The uranium 235 used in thermal nuclear reactors undergoes fission more readily when struck by slow neutrons than when struck by the fast neutrons released by fission. Also called thermal neutron Compare fast neutron.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.