Determination of Plutonium Isotopic Composition at sub-Picogram Levels

摘要

A method was developed for the determination of plutonium isotopic composition at the sub-picogram level. Investigations of mass spectral backgrounds and of means of concentrating and purifying sample plutonium were conducted. Isotopic measurements were made by alpha energy analysis and mass spectrometric analysis. A technique for evaluating mass spectral background with a plutonium spike enriched in the mass 239 isotope to 99.98 atom percent is described. A combined alpha energy-mass analysis procedure for the determination of isotopic composition on a single sample mount is reported. The data presented demonstrate that sources of environmentally occurring plutonium could be differentiated by isotopic composition analysis with the developed method even at sub-picogram levels. (ERA citation 02:014298)