A neutron (see also baryon) is a fundamental component of a nucleus. Neutrons, discovered by James Chadwick in 1935 (Nobel Prize in physics), have no charge and are about 1838 times more massive than electrons.

See also Neutron Activation, Neutron Activation Analysis, Neutron Radiation and Neutron Capture.

Neutron capture is a process in which a neutron collides with a nucleus and becomes part of this nucleus caused by nuclear forces. It interacts without release of another heavy particle. A gamma ray photon is emitted as an immediate result of the neutron capture process. Through the neutron capture the nucleus becomes a heavier isotope of the same element. The kind of decay depends on the isotope and its stability.
This process is for example part of the neutron activation analysis, in which a sample is positioned in a neutron beam and also used in the 'boron neutron capture therapy'.

See also Thermal Neutrons, Epithermal Neutron, Neutron Activation Analysis, Nuclear Charge Number, Deuteron, Isomeric Transition, Isotones, N P Reaction.

Slow neutrons have a speed of around 2.2 km/s (0.025 eV). They could be generated in a reactor and could lead, because of their much larger effective neutron absorption cross-section than quick neutrons, to neutron activation.

See also Neutron Activation, Neutron Activation Analysis, Neutron Capture and Neutron Radiation.

Neutron radiation is one type of ionizing radiation. Neutrons get emitted from an atom by the fission process or by decay processes. In the upper atmosphere neutron radiation is produced by the interaction of cosmic radiation with air. Neutron radiation is used for the production of medical isotopes and certain direct medical therapies.

See also Neutron Activation, Neutron Activation Analysis and Neutron Capture.

Epithermal neutrons are unbound moderately severe neutrons. The energy of epithermal neutrons is in the range from 0.025 to 1 eV. Unbound neutrons are produced in fission and in some radioactive decay processes.

See also Neutron Activation Analysis, Neutron Capture.