Investigation on the fission track analysis of uranium-doped particles for the screening of safeguards environmental samples

The fission track (FT) method was used for the screening of swipes, which are used to identify the undeclared nuclear activities in suspected facilities. This research is performed in order to establish the screening technology of swipes prior to a mass spectroscopic determination. Various sized uranium-doped silica particles with different enrichment were used as reference materials for the quick determination of the 235U enrichments. The particle size of the reference materials were in the ranges from 2 to 20 μm and the 235U enrichments of the reference materials were in the range from 1% to 50%. The correlation of the FT characteristics, such as a cluster diameter, a over-etched cluster core diameter, and a cluster depth, with the particle size and the 235U enrichments were determined within a reasonable confidence limit. The developed technique was applied for the determination of the enrichment factor for environmental particle samples with an unknown isotope ratio.