title: Standardization of 89Sr.
abstract: Two methods were used for the standardization of the pure beta-emitter 59Sr solution received in the framework of the 2000 BIPM comparison of activity measurements. The first method was by scintillation counting using the triple to double coincidence ratio (TDCR) technique. The existing three detector-system was improved by the inclusion of a MAC-3 module produced by LNHB-Saclay. This module contains the circuits for the coincidence, dead time and gate functions. This was the first use of this equipment in an international comparison. The DETECSZ program (LNHB) was used to obtain the activity concentration, at the reference time, as 26.09+/-0.21 kBq g(-1). The second method was the efficiency tracer technique, using a 60Co standard solution and a 4pi beta-gamma-coincidence system. The radioactivity concentration was calculated from a general extrapolation curve, by using data from several sources. The value was 26.58+/-0.28 kBq g(-1) on the reference date 01.10.2000, 00 h UTC. The two results are in agreement within the limits of their combined uncertainties.
authors.affiliation: National Institute of R&D for Physics and Nuclear Engineering Horia Hulubei, IFIN-HH, Bucharest, Romania.
authors.forename: Anamaria Cristina
authors.initials: AC
authors.lastname: Razdolescu
authors.forename: Maria
authors.initials: M
authors.lastname: Sahagia
authors.forename: Ph
authors.initials: P
authors.lastname: Cassette
authors.forename: E L
authors.initials: EL
authors.lastname: Grigorescu
authors.forename: A
authors.initials: A
authors.lastname: Luca
authors.forename: C
authors.initials: C
authors.lastname: Ivan