title: Standardization of 204Tl and 89Sr at VNIIM.
abstract: D.I. Mendeleyev Institute for Metrology (VNIIM) participated in two international comparisons of 204Tl and 89Sr solutions organized by the BIPM. The activity concentration was measured using the 4pi PC beta-counting method. Special attention was paid for investigating the dependence of the result on the inner diameter of the source support ring. For thin Al rings (100-200 microm), no dependence was detected. The beta-impurities in the 89Sr solution were determined using a scintillation plastic spectrometer. The combined standard uncertainty of the standardization of the 89Sr solution is 0.2%, and that for 204Tl is 0.4%.
authors.affiliation: D.I. Mendeleyer Institute for Metrology (VNIIM), St. Petersburg, Russia. info2101@vniim.ru
authors.forename: T E
authors.initials: TE
authors.lastname: Sazonova
authors.forename: A E
authors.initials: AE
authors.lastname: Kochin
authors.forename: N I
authors.initials: NI
authors.lastname: Karmalitsyn
authors.forename: S V
authors.initials: SV
authors.lastname: Sepman
authors.forename: A V
authors.initials: AV
authors.lastname: Zanevsky
authors.forename: T I
authors.initials: TI
authors.lastname: Shilnikova