Ultra-trace analysis of plutonium isotopes by thermal ionization mass spectrometry with a continuous heating technique without chemical separation

Lee, C. G.*; Suzuki, Daisuke   ; Esaka, Fumitaka  ; Magara, Masaaki  ; Song, K.*

In this study, analytical performances of TIMS with a continuous heating method were investigated using plutonium standard solution (SRM 947) and mixed particulate sample containing plutonium (SRM947) and uranium (U500). In order to examine the analytical performance of plutonium solution sample, the influence of heating rate of evaporation filament on precision and accuracy of isotope ratios was studied using plutonium solution sample of fg level. Changing the heating rate of evaporation filament on samples ranging from 0.1 fg to 1000 fg revealed that no influence of heating rate on precision and accuracy of isotope ratios occurred over the heating rate range from 100 to 250 mA/min. All of the isotope ratios on plutonium were measured down to sample amounts of 70 fg. In the mixture samples of plutonium and uranium, Pu and U were clearly distinguished due to the difference of evaporation temperature between Pu and U. As a result, the ratios of plutonium sample were successfully measured by TIMS with a continuous heating technique without any chemical separations.