title: 57Co half-life determination.
abstract: The National Laboratory for Metrology of Ionizing Radiation (LNMRI)/Brazil participated in the last (57)Co activity measurement comparison organized by IAEA, in 2008. This was made in order to realize primary standardization of this radionuclide and to reduce the measuring uncertainties in the laboratory. Additionally, one sample with 2.6g was taken from the IAEA master solution of (57)Co and was prepared to be used in the measurement of the radionuclide's half-life in an ionization chamber system. The (57)Co half-life was measured to be 271.82 (17) days.
authors.affiliation: Laboratório Nacional de Metrologia das Radiações Ionizantes (LNMRI), Instituto de Radioproteção e Dosimetria (IRD), Comissão Nacional de Energia Nuclear (CNEN), Av. Salvador Allende, s/no Recreio, CEP 22780-160 Rio de Janeiro, Brazil. Carlos@ird.gov.br
authors.forename: C J
authors.initials: CJ
authors.lastname: da Silva
authors.forename: A
authors.initials: A
authors.lastname: Iwahara
authors.forename: D S
authors.initials: DS
authors.lastname: Moreira
authors.forename: J U
authors.initials: JU
authors.lastname: Delgado
authors.forename: R S
authors.initials: RS
authors.lastname: Gomes
mesh_terms: D001938:Brazil; D003037:Cobalt Radioisotopes / Q000032:analysis* / Q000737:chemistry*; D006207:Half-Life; D038622:Internationality; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000592:standards*; D012015:Reference Standards; D012016:Reference Values
chemical_list: D003037:Cobalt Radioisotopes