title: Primary activity standardization of ⁹⁹Tc by three different absolute methods.
abstract: The activity concentration of a solution of (99)Tc was absolutely determined by liquid scintillation measurements based on the triple-to double-coincidence ratio method (TDCR) and compared with the results given by 4πβ(LS)-γ(NaI) live-timed anticoincidence (with extending dead-time) and classical 4πβ(PC)-γ(NaI) coincidence counting systems based on using (60)Co as the efficiency-tracing radionuclide. The results of anticoincidence and coincidence counting are, respectively, 0.18% and 0.66% higher than the result from TDCR measurements, but they are consistent within uncertainties.
authors.affiliation: Laboratório Nacional de Metrologia das Radiações Ionizantes/Instituto de Radioproteção e Dosimetria/Comissão Nacional de Energia Nuclear (LNMRI/IRD/CNEN), Av. Salvador Allende, s/no - Barra da Tijuca, CEP 22783-127, Rio de Janeiro, Brazil.
authors.forename: Paulo A L
authors.initials: PA
authors.lastname: da Cruz
authors.affiliation: Laboratório Nacional de Metrologia das Radiações Ionizantes/Instituto de Radioproteção e Dosimetria/Comissão Nacional de Energia Nuclear (LNMRI/IRD/CNEN), Av. Salvador Allende, s/no - Barra da Tijuca, CEP 22783-127, Rio de Janeiro, Brazil.
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: da Silva
authors.affiliation: Laboratório Nacional de Metrologia das Radiações Ionizantes/Instituto de Radioproteção e Dosimetria/Comissão Nacional de Energia Nuclear (LNMRI/IRD/CNEN), Av. Salvador Allende, s/no - Barra da Tijuca, CEP 22783-127, Rio de Janeiro, Brazil.
authors.forename: Denise S
authors.initials: DS
authors.lastname: Moreira
authors.affiliation: Laboratório Nacional de Metrologia das Radiações Ionizantes/Instituto de Radioproteção e Dosimetria/Comissão Nacional de Energia Nuclear (LNMRI/IRD/CNEN), Av. Salvador Allende, s/no - Barra da Tijuca, CEP 22783-127, Rio de Janeiro, Brazil. Electronic address: iwahara@ird.gov.br.
authors.forename: Akira
authors.initials: A
authors.lastname: Iwahara
authors.affiliation: Fundação Carlos Chagas Filho de Apoio à Pesquisa do Estado de Rio de Janeiro (FAPERJ), Av. Erasmo Braga, 118-6° andar - Centro, CEP 20020-000, Rio de Janeiro, Brazil.
authors.forename: Luiz
authors.initials: L
authors.lastname: Tauhata
authors.affiliation: Programa de Engenharia Nuclear, Universidade Federal do Rio de Janeiro (PEN/COPPE, UFRJ), Ilha do Fundão, Caixa Postal 68590, CEP 21945-970, Rio de Janeiro, Brazil.
authors.forename: Ricardo T
authors.initials: RT
authors.lastname: Lopes
keywords: (99)Tc; Classical coincidence; Live-timed anticoincidence; TDCR