Direct isotope ratio analysis of individual uranium-plutonium mixed particles with various U/Pu ratios by thermal ionization mass spectrometry

摘要

Uranium and plutonium isotope ratios in individual uranium-plutonium (U-Pu) mixed particles with various U/Pu atomic ratios were analyzed without prior chemical separation by thermal ionization mass' spectrometry (TIMS). Prior to measurement, micron-sized particles with U/Pu ratios of 1, 5, 10, 18, and 70 were produced from uranium and plutonium certified reference materials. In the TIMS analysis, the peaks of americium, plutonium, and uranium ion signals were successfully separated by continuously increasing the evaporation filament current. Consequently, the uranium and plutonium isotope ratios, except the Pu-238/Pu-239 ratio, were successfully determined for the particles at all U/Pu ratios. This indicates that TIMS direct analysis allows for the measurement of individual U-Pu mixed particles without prior chemical separation. (C) 2014 Elsevier Ltd. All rights reserved.