title: IRMM-1000a and IRMM-1000b: uranium reference materials certified for the production date based on the230Th/234U radiochronometer. Part II: certification.
abstract: The IRMM-1000a and IRMM-1000b uranium reference materials, of 20 and 50 mg uranium, respectively, were produced by the European Commission Joint Research Centre's Institute for Reference Materials and Measurements (EC-JRC-IRMM) in collaboration with the Institute for Transuranium Elements (EC-JRC-ITU). They are novel uranium reference materials certified for the production date based on the230Th/234U radiochronometer, i.e. the date of the last chemical separation of these two radionuclides. The certified reference value and its uncertainty, homogeneity and stability of the material were established in accordance with the ISO Guide 34:2009 and the 'Guide to the Expression of Uncertainty in Measurement'.
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Venchiarutti
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors.forename: Z
authors.initials: Z
authors.lastname: Varga
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Richter
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Nicholl
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Krajko
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Jakopič
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Mayer
authors.affiliation: European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Aregbe
keywords: 230Th/234U radiochronometer; CRMs; Certified reference material; Nuclear safeguards and forensics; Uranium age-dating