Secondary ion mass spectrometry combined with alpha track detection for isotope abundance ratio analysis of individual uranium-bearing particles

Esaka, Fumitaka  ; Magara, Masaaki  

Secondary ion mass spectrometry (SIMS) was used in combination with alpha track detection for the efficient analysis of uranium-bearing particles with higher U abundances in environmental samples. A polycarbonate film containing particles was prepared and placed in contact with a CR-39 plastic detector sheet. After exposure, the sheet was etched in NaOH solution and each uranium-bearing particle was identified through observation of the alpha tracks recorded in the sheet. A portion of the film containing each uranium-bearing particle was cut out and put onto a glassy carbon planchet. The films on the planchet were decomposed through plasma ashing for subsequent uranium abundance ratio analysis with SIMS. The alpha track - SIMS analysis for ten uranium-bearing particles in a sample taken from a nuclear facility afforded (U)/(U) abundance ratios in the range 0.0072 to 0.25, which were significantly higher than those obtained by SIMS without alpha track detection.