Immediate emission of neutrons after nuclear fission
In nuclear engineering, a prompt neutron is a neutron immediately emitted (neutron emission) by a nuclear fission event, as opposed to a delayed neutron decay which can occur within the same context, emitted after beta decay of one of the fission products anytime from a few milliseconds to a few minutes later.
Prompt neutrons emerge from the fission of an unstable fissionable or fissile heavy nucleus almost instantaneously. There are different definitions for how long it takes for a prompt neutron to emerge. For example, the United States Department of Energy defines a prompt neutron as a neutron born from fission within 10−13 seconds after the fission event.[1] The U.S. Nuclear Regulatory Commission defines a prompt neutron as a neutron emerging from fission within 10−14 seconds.[2]
This emission is controlled by the nuclear force and is extremely fast. By contrast, so-called delayed neutrons are delayed by the time delay associated with beta decay (mediated by the weak force) to the precursor excited nuclide, after which neutron emission happens on a prompt time scale (i.e., almost immediately).
^"DOE Fundamentals Handbook - Nuclear Physics and Reactor Theory" (PDF), DOE Fundamentals Handbook - Nuclear Physics and Reactor Theory, DOE-HDBK-1019/1-93, U.S. Department of Energy, January 1993, p. 29 (p. 133 of .pdf format)
^Mihalczo, John T. (November 19, 2004), "Radiation Detection From Fission" (PDF), Radiation Detection From Fission, ORNL/TM-2004/234, Oak Ridge National Laboratory, p. 1 (p. 11 of .pdf format)
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containing PromptPromptneutron, in nuclear engineering Prompt criticality This disambiguation page lists articles associated with the title Prompt. If an...
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"Solar Gamma Ray and Neutron Observations". NASA Special Publication. 342: 285. Bibcode:1973NASSP.342..285C. Prompt Gamma-ray Neutron Activation Analysis...
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one of its neutrons. In nuclear engineering, a promptneutron is a neutron immediately emitted by a nuclear fission event. Promptneutrons emerge from...
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