Isotopic analysis of single uranium and plutonium particles by chemical treatment and mass spectrometry

Shinonaga, Taeko*; Esaka, Fumitaka  ; Magara, Masaaki  ; Klose, D.*; Donohue, D.*

The isotopic composition of single uranium and plutonium particles was measured with an inductively coupled plasma mass spectrometer (ICP-MS) and a thermal ionization mass spectrometer (TIMS). The particles prepared on a carbon planchet were first analyzed with an energy dispersive X-ray spectrometer (EDX) attached to a scanning electron microscope (SEM) and then transferred on to a silicon wafer using a manipulator. The particle on the silicon wafer was dissolved with nitric acid and the isotopic ratios of U and Pu were measured with ICP-MS and TIMS. The results obtained by both methods showed good agreement with the certified values within the expected uncertainty. The measurement uncertainties obtained in this study were similar for both mass spectrometric methods. This study was performed to establish the method of particle analysis with SEM, EDX, the particle manipulation technique, and the measurement of isotope ratios of U and Pu in a single particle by mass spectrometry.