γ-rays from an unirradiated plutonium-uranium oxide fuel pin and a method of measuring the age of plutonium since chemical processing

An analysis of the γ-ray spectra of a plutonium-uranium oxide fuel pin and of pure 241Am leads to a proposed method of dating the plutonium's last chemical separation process. It depends on branching in the decay of 241Pu. The intensities of suitable γ-rays in each branch are compared. Several such γ-rays are proposed and their use examined. The age of any macroscopic sample of plutonium may be determined noninvasively by a comparison at a single time with a similar sample of the same dimensions and of known age. (author)