Developing combined fission track analysis and alpha track analysis to study the spatial distribution of U and Pu sorbed to environmental particles

Fission track analysis (FTA) is a direct technique to detect trace amounts of nuclides with high fission cross sections. To improve the capability of finding the exact location of contaminated particles in a sample, we have investigated combining alpha track analysis (ATA) with FTA in a single track detector. Alpha tracks are used to record the image of a scanning electron microscopy (SEM) finder grid in a LEXAN track detector, along with fission tracks from ²³⁵U-coated particles. The SEM finder grid was coated with B, and alpha tracks were obtained by the ¹⁰B(n, α)⁷Li nuclear reaction. U-contaminated environmental particles were simulated by sorbing U to ion exchange beads. Images were obtained by neutron irradiation and chemical etching. In this paper, we describe our method and possible applications. (author)