any of several devices in which a chain reaction is initiated and controlled with the resulting heat typically used for power generation and the neutrons and fission products used for military, experimental, and medical purposes.
particle accelerator
a device, such as a cyclotron or linear accelerator, that accelerates charged subatomic particles or nuclei to high energies
radioactivity
spontaneous emission of radiation, either directly from unstable atomic nuclei or as a consequence of a nuclear reaction
half-life
the time required for half the nuclei in a sample of a specific isotopic species to undergo decay
bombardment
act (or an instance) of subjecting a body or substance to the impact of high-energy particles
isotope
one of two or more atoms having the same atomic number but different mass numbers, due to a different number of neutrons in the nucleus
fission
a nuclear reaction in which an atomic nucleus, especially a heavy nucleus such as an isotope of uranium, splits into fragments, usually two fragments of comparable mass, releasing from 100 million to several hundred million electron volts of energy
nucleon
a proton or a neutron, especially as part of an atomic nucleus
fusion
a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
alpha particle
positively charged particle, indistinguishable from a helium atom nucleus and consisting of two protons and two neutrons
