Accurate purification age determination of individual uranium-plutonium mixed particles

Miyamoto, Yutaka   ; Suzuki, Daisuke   ; Esaka, Fumitaka  ; Magara, Masaaki  

Age of individual uranium-plutonium mixed particles with various U/Pu atomic ratios were determined by inductively-coupled plasma mass spectrometry. Micron-sized particles were prepared from U and Pu certified reference materials. The Pu reference was stored for 4-6 years since the last purification. The Pu purification age was obtained from the Am/Pu ratio which was calculated from the product of three measured ratios of Pu and Am isotopes in the eluted fractions. Am, U and Pu in a sample solution were sequentially separated a small anion-exchange column. The Am/Pu ratio was accurately determined by spiking pure Am to the sample solution. The determined age of particles with various U/Pu ratios was in good agreement with the expected age with high accuracy and high precision.