neutron source
英[ˈnu:ˌtrɔn sɔ:s]美[ˈnuˌtrɑn sɔrs]
A neutron source is a device that emits neutrons. There exist a wide variety of neutron sources of differing mechanism and size, ranging from hand-held radioactive sources and tabletop electrically powered neutron generators, to large neutron research facilities operating research reactors and spallation sources.