Thus, a neutron source can be fabricated by mixing an alpha-emitter such as radium, polonium, or americium with a low-atomic-weight isotope, usually by blending powders of the two materials.
Two example reactions are: Some accelerator-based neutron generators induce fusion between beams of deuterium and/or tritium ions and metal hydride targets which also contain these isotopes.
Inertial electrostatic confinement devices such as the Farnsworth-Hirsch fusor use an electric field to heat a plasma to fusion conditions and produce neutrons.
[1] Nuclear fission within a reactor, produces many neutrons and can be used for a variety of purposes including power generation and experiments.
Nuclear fusion, the fusing of heavy isotopes of hydrogen, has the potential to produces large numbers of neutrons.
Small scale fusion systems exist for (plasma) research purposes at many universities and laboratories around the world.
Subcritical nuclear fission reactors are proposed to use spallation neutron sources and can be used both for nuclear transmutation (e.g. production of medical radionuclides or synthesis of precious metals) and for power generation as the energy required to produce one spallation neutron (~30 MeV at current technology levels) is almost an order of magnitude lower than the energy released by fission (~200 MeV for most fissile actinides).
When high-power lasers interact with dense targets, they generate high-energy particles such as protons or deuterons, which can then collide with a secondary material, inducing neutron emission.
These sources are compact compared to traditional spallation or reactor-based facilities and provide unique capabilities, including ultra-short neutron bursts and high brilliance.