Page "Neutron activation analysis" Paragraph 1

Neutron activation analysis is a sensitive multi-element analytical technique used for both qualitative and quantitative analysis of major, minor, trace and rare elements.

NAA was discovered in 1936 by Hevesy and Levi, who found that samples containing certain rare earth elements became highly radioactive after exposure to a source of neutrons.

This observation led to the use of induced radioactivity for the identification of elements.

NAA is significantly different from other spectroscopic analytical techniques in that it is based not on electronic transitions but on nuclear transitions.

To carry out an NAA analysis the specimen is placed into a suitable irradiation facility and bombarded with neutrons.

This creates artificial radioisotopes of the elements present.

Following irradiation the artificial radioisotopes decay via the emission of particles or more importantly gamma rays, which are characteristic of the element from which they were emitted.