title: Characterization of uranium particles produced by hydrolysis of UF6 using SEM and SIMS.
abstract: Environmental sampling (ES) is a powerful technique used by safeguards inspectors of the International Atomic Energy Agency and the European Safeguards Office for the detection of undeclared nuclear activities. Since its implementation in the 1990s, ES has proven to be very sensitive and effective. Considering the consequences, the measurements should be carried out under a quality management programme. At the Institute for Reference Materials and Measurements, a new production method is under development for the preparation of reference uranium particles from well-certified UF6, allowing uranium particles with certified isotopic abundances to be prepared that are representative of those found in uranium enrichment facilities. Using an aerosol deposition chamber designed and built for the purpose, particles are formed by the hydrolysis of UF6 and their morphology and (isotopic) composition measured using SEM-EDX and SIMS. The SEM measurements show that by varying the relative humidity of the air in the reaction chamber, the morphology of the particles can be changed. By making a distribution map of the chemical composition of the particles, the relationship between fluorine and uranium as main constituents of the particle could be established. The presence of fluorine is a valuable indicator for the occurrence of nondeclared enrichment activities.
authors.affiliation: European Commission, General Directorate Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel, Belgium. ruth.kips@ec.europa.eu
authors.forename: Ruth
authors.initials: R
authors.lastname: Kips
authors.forename: Ann
authors.initials: A
authors.lastname: Leenaers
authors.forename: Gabriele
authors.initials: G
authors.lastname: Tamborini
authors.forename: Maria
authors.initials: M
authors.lastname: Betti
authors.forename: Sven
authors.initials: S
authors.lastname: Van den Berghe
authors.forename: Roger
authors.initials: R
authors.lastname: Wellum
authors.forename: Philip
authors.initials: P
authors.lastname: Taylor