Computer-assisted qualitative analysis of gamma-ray spectra

A computer program is described to perform the identification of isotopes in neutron activated samples. The γ-ray energies as obtained from a Ge(Li) γ-ray spectrum are compared with those of a library, containing data for about 250 isotopes. Isotopes whose γ-ray energies match closely with the unknowns are selected as possible constituents. Unlikely attributions are then eliminated by a careful inspection of the γ-rays found. Further exploitation of half-life, the way of production and the sensitivity for the given irradiation and measurement conditions, allow the selection of the most likely constituents in the source. The results of the automated identification agree closely to those obtained by an experienced investigator. The program is written in FORTRAN IV for a PDP-9 computer with a 16 K word memory.