Application of continuous heating method by thermal ionization mass spectrometry for measurement of isotope ratios of plutonium and uranium in trace amount of MOX sample

Kokubu, Yoko; Suzuki, Daisuke; Lee, C. G.; Magara, Masaaki; Shinohara, Nobuo; Kimura, Takaumi

Recently it becomes important to develop analytical technique of small particle consisted of MOX for analysis of safeguards environmental samples. Continuous heating method by thermal ionization mass spectrometry was applied to simultaneous measurement of isotope ratios of plutonium and uranium in trace amount of MOX sample. As the method was developed for isotope ratio measurement of U, measurement conditions were optimized for analysis of MOX sample. The results of the isotope ratios (Pu/Pu and U/U) in a mixed sample containing isotope ratio standards of Pu and U were in good agreement with the certified values within the standard deviation. The method enabled us to measure isotope ratios without chemical separation of U and Pu.