Fast neutron

Fast Neutron

A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (Mega electron Volts), hence a speed of 14,000 km/s, or higher. They are named fast neutrons to distinguish them from lower-energy thermal neutrons, and high-energy neutrons produced in cosmic showers or accelerators.

Production[edit | edit source]

Fast neutrons are produced by nuclear processes such as nuclear fission or nuclear fusion. They are also found in cosmic rays. Fast neutrons can be made into thermal neutrons via a process called moderation. This is done in a nuclear reactor using a neutron moderator.

Interaction with matter[edit | edit source]

Fast neutrons are most effectively absorbed by hydrogen nuclei, so they can be slowed down or "moderated" by substances containing hydrogen, like water or polyethylene. They can also be absorbed by a neutron absorber that reduces their kinetic energy, or they can be scattered out of the system.

Uses[edit | edit source]

Fast neutrons can be used in nuclear reactors, and they are essential to the basic operation of most nuclear reactors. Fast neutron reactors, specifically, are a type of nuclear fission reactor in which the fission chain reaction is sustained by fast neutrons. Such a reactor needs no neutron moderator, but requires fuel that is relatively rich in fissile material when compared to that required by a thermal reactor.

Health hazards[edit | edit source]

Fast neutrons are high radiation hazards. They have a high quality factor for radiation protection purposes, and their presence requires protective shielding.

References[edit | edit source]

Fast neutron Resources
Need Help Finding a Doctor? Need help finding a doctor or specialist anywhere in the world? Explore our world directory. WikiMD's DocFinder can assist you in locating millions of physicians.	Medical Knowledge Access the latest research - Most recent articles Ongoing trials.