DETERMINATION OF PLUTONIUM IN NUCLEAR-MATERIALS WITH THE COMBINATION OF ALPHA-SPECTROMETRY AND GAMMA-SPECTROMETRY

Alpha-particle spectrometry (AS) and high-resolution gamma spectrometr y (HRGS) are jointly used for the determination of plutonium concentra tion in various materials containing this element. With AS the alpha a ctivity ratios of Pu-238/(Pu-239 + Pu-240) in spiked and unspiked samp les and with HRGS the isotopic composition of plutonium in unspiked sa mples have been measured. The plutonium concentrations are calculated from the isotope dilution formula and are compared with the results fr om isotope dilution mass spectrometry (IDMS). The relative differences between the results of both methods are within +/-1%. Several factors such as the quality of alpha sources, sample size and the errors in H RGS affect the results and they are discussed in detail.