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.

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.

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.

(NAA) Neutron activation analysis is a very sensitive analytical technique to determine even very low concentration of chemical elements, trace elements for example, in small biological samples.
NAA becomes commercial available in the USA in 1960.
In the activation process stable nuclides in the sample, which is placed in a neutron beam (neutron flux, 90-95% are thermal neutron with low energy levels under 0.5 eV), will change to radioactive nuclides through neutron capture (artificial radioactivity). These radioactive nuclides decay by emitting alpha-, beta-particles and gamma-rays with a unique half-life. Qualitative and quantitative analysis of the sample is done with a high-resolution gamma-ray spectrometer.
NAA is subdivided into the following techniques:

A sample is placed into a concentrated beam of neutrons. Through neutron-capture heavier nuclei become frequently unstable. This artificial radiation decays with a characteristic half-live consisting of alpha- and beta-particles and gamma-rays.

See Neutron Activation Analysis