Vacuum Suction-Impact Collection for Recovering Uranium Particles From Swipe Sample

A new particle recovery method from safeguards swipe samples was developed for subsequent isotope ratio analysis of uranium particles by secondary ion mass spectrometry （SIMS）. The particles were determined and counted by scanning electron microscope(SEM). The recovery efficiency is about (43±5)% for PbO particles and about 48% for uranium particles respectively. The dispersion of recovery particles is satisfied. The samples prepared by this method were measured by SIMS. The average isotope ratio of ²³⁵U/²³⁸U for individual natural uranium particles is 0.007 25±0.000 09 with a standard deviation less than 3%.