Isotopic Measurements of U particles by Secondary Ionisation Mass Spectrometry (SIMS)

The most common environmental samples taken by IAEA Safeguards inspectors are dust samples collected on cotton swipes. The isotopic analysis of particles from these samples is one of IAEA’s main tools to verify the absence of non-declared nuclear material handling and has since it was first introduced in the early 1990’s been proven as a reliable and extremely sensitive technique. IAEA’s environmental samples are analysed at the Safeguards Analytical Laboratory (SAL) and/or by a laboratory in an international network highly specialized in this type of analysis. The isotopic analysis of U particles at SAL is done by the use of Secondary Ion Mass Spectrometry (SIMS). The analytical SIMS work includes sample preparation, screening methods to locate U particles in a matrix of other material and the final isotopic measurements of individual particles. This paper presents an overview on the status and SAL’s program for analytical improvements in the analysis of U particles by SIMS.