Fast neutron

A fast neutron is a type of neutron with high energy, moving at velocities typically above 1 million meters per second. Neutrons are subatomic particles found in the nucleus of an atom, and when they are fast, they carry significant kinetic energy. They are often produced in nuclear reactions, such as in reactors or during radioactive decay. Fast neutrons can penetrate materials more deeply than slow (thermal) neutrons, making them important in nuclear science, radiation therapy, and materials research. Their high energy makes them capable of initiating nuclear reactions or causing atomic changes in materials they encounter.