title: Standardization of 152Eu.
abstract: 152Eu was standardized within the frame of a BIPM international comparison. The solution was prepared and bottled by PTB. The ampoules were measured at BIPM in the SIR ionization chambers and then dispatched to the participating laboratories. In the Radionuclide Metrology Laboratory of IFIN-HH, the solution was standardized using a coincidence method with "beta-efficiency extrapolation" by foil absorption. A simple 4pi beta-gamma-coincidence system was used, with NaI(Tl) and 4piPC detectors. No significant impurities were found apart for 0.5% 154Eu. To obtain linear extrapolation plots, a "gamma-window" of 180-1500 keV was chosen. Dead-times of 10 micros were used. A combined uncertainty of 0.24% was obtained, mainly from the extrapolation procedure component.
authors.affiliation: National Institute of R&D for Physics and Nuclear Engineering, Horia Hulubei, (IFIN-HH), Bucharest-Magurele, Romania. elgrigorescu@yahoo.com
authors.forename: E L
authors.initials: EL
authors.lastname: Grigorescu
authors.forename: Anamaria Cristina
authors.initials: AC
authors.lastname: Razdolescu
authors.forename: Maria
authors.initials: M
authors.lastname: Sahagia
authors.forename: A
authors.initials: A
authors.lastname: Luca
authors.forename: C
authors.initials: C
authors.lastname: Ivan
authors.forename: G
authors.initials: G
authors.lastname: Tanase