Investigations on atomic and oxide ion formation of plutonium and uranium in thermal ionization mass spectrometry (TIMS) for determination of 238Pu

Studies are reported on the atomic and oxide ion formation of Pu and U during thermal ionization mass spectrometry. Different synthetic mixtures with Pu/U amount ratios of 2-10 were used to study the vaporization and ionization characteristics under different heating currents of vaporization and ionization filaments using a double filament assembly. The different ions observed were U+, Pu+, UO+, PuO+ and two different sets of filament heating conditions were identified to maximize the production of UO+ and Pu+ ions. It is observed that by using interfering element correction methodology and employing suitable filament heating currents, there exists a potential of determining Pu-238 in Pu samples by TIMS with accurate accounting of isobaric interference from U-238. (C) 2004 Elsevier B.V. All rights reserved.