Affiliations: Department of Geology, McMaster University, Hamilton, Ontario, Canada L8S 4M1
Abstract: Prompt gamma neutron activation analysis is concerned with the detection of a nucleus which undergoes neutron capture, followed by particle or radiation emission, in a time period of < 10−12 s. As usually practised, the emitted radiation is detected and measured while a sample is being irradiated in a reactor neutron beam. After the recognition of neutron capture in the mid-1930s, analytical procedures for elements of high capture cross-section, such as B, Cd, H, Sm and others, had to await the development of thermalised neutron beams and high-resolution detectors, from the mid-1960s on. Analysis theory is based on the (simplified) principle that gamma counts measured are in direct proportion to the number of atoms of the target isotope of the element in the irradiated sample. Practical details of instrumentation depend on the reactor geometry and other factors. PGNAA is a simple, fast and effective analytical procedure, and future development depends on reactor design and construction.
