title: Standardization of Tc-99 by three liquid scintillation counting methods.
abstract: The NMISA participated in the international key comparison of the pure beta-emitter Technetium-99, CCRI(II)-K2.Tc-99. The comparison solution was standardized using three methods, namely the TDCR efficiency calculation method, the CIEMAT/NIST efficiency tracing method and the 4π(LS)β-γ coincidence tracing method with Co-60 as tracer. Excellent agreement between results obtained with the three methods confirmed the applicability of the beta spectral shape given by the latest (2011) DDEP evaluation of Tc-99 decay data, rather than the earlier (2004) evaluation.
authors: National Metrology Institute of South Africa, 15 Lower Hope Road, Rosebank, 7700 Cape Town, South Africa. Electronic address: radioactivity@nmisa.org.
authors: W M
authors: WM
authors: van Wyngaardt
authors: National Metrology Institute of South Africa, 15 Lower Hope Road, Rosebank, 7700 Cape Town, South Africa.
authors: M J
authors: MJ
authors: van Staden
authors: National Metrology Institute of South Africa, 15 Lower Hope Road, Rosebank, 7700 Cape Town, South Africa.
authors: J
authors: J
authors: Lubbe
authors: National Metrology Institute of South Africa, 15 Lower Hope Road, Rosebank, 7700 Cape Town, South Africa.
authors: B R S
authors: BR
authors: Simpson
keywords: 4π(LS)β–γ coincidence tracing; Beta spectral shape; CNET; Liquid scintillation counting; TDCR; Technetium-99