Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
prompt neutron
Introduction References & Edit History Related Topics
Quick Facts
Related Topics:
nuclear fission
See all related content
Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what youā€™ve submitted and determine whether to revise the article.

External Websites

prompt neutron

nuclear particle
Written and fact-checked by
Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
Britannica Editors
History

prompt neutron, in nuclear fission reactions, neutron emitted instantaneously by a nucleus undergoing fissionā€”in contrast to a delayed neutron, which is emitted by an excited nucleus among the fission products at an appreciable time interval (milliseconds to minutes) after fission has occurred. Most neutrons released in fission reactions are prompt; for example, only about 0.7 percent of the neutrons emitted in uranium-235 fission are delayed.

This article was most recently revised and updated by William L. Hosch.