- a neutron produced by nuclear fission that has lost little energy by collision; a neutron with a kinetic energy in excess of 0.1 MeV
- a neutron with a kinetic energy in excess of 1.5 MeV, the fission threshold of uranium-238
Gearhead Slang For The Fast LaneCan you speak car slang? Here are some words the gearhead (or "car fanatic") in your life probably knows and uses at weekly car meets or on the forum.
Where Did The Phrase “Fast And The Furious” Come From?The continued box office success of the Fast and the Furious franchise gives moviegoers and word-lovers something to cheer about. Beyond the stunning action sequences, though, audiences, including us, actually really enjoy the title itself.
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
Science definitions for fast neutron
A neutron that is not in thermal equilibrium with the surrounding medium, especially one produced by fission. Compare slow neutron. See also fast-breeder reactor.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.