title: Standardization and decay data determinations of 125I, 54Mn and 203Hg.
abstract: The absolute 4pi-betagamma coincidence counting has been used to measure the activity concentrations of 54Mn and 203Hg, and the Sum-Peak method was used for 125I. 54Mn and 125I radionuclides have been part of international key-comparisons coordinated by the Bureau International des Poids et Measures (BIPM) in 2003/2004, while 203Hg is part of the traceability programme of the National Laboratory for Ionizing Radiation Metrology (LNMRI)/Brazil. Three different detectors were used for the Sum-Peak method: 3''x3'' NaI(Tl) and 5''x5'' well NaI(Tl) scintillation detectors and a planar germanium detector. Direct measurements were made of the photon emission probabilities of the 35.5-, 834.8- and 279.2-keV gamma-rays of 125I, 54Mn and 203Hg to give values of (0.0667+/-0.0014), (0.9997+/-0.0055) and (0.8161+/-0.0005), respectively. The half-lives of 203Hg and 54Mn were also determined by means of a 4pigamma ionization chamber (203Hg) and by the reference source method using a HPGe detector (54Mn) to give values of (46.639+/-0.023) days and (312.1+/-0.9) days, respectively.
authors.affiliation: Laboratório de Instrumentação Nuclear (LIN/PEN/COPPE/UFRJ), Caixa Postal 68509, CEP 21945-970, Rio de Janeiro, Brazil.
authors.forename: M A L
authors.initials: MA
authors.lastname: da Silva
authors.forename: R
authors.initials: R
authors.lastname: Poledna
authors.forename: A
authors.initials: A
authors.lastname: Iwahara
authors.forename: C J
authors.initials: CJ
authors.lastname: da Silva
authors.forename: J U
authors.initials: JU
authors.lastname: Delgado
authors.forename: R T
authors.initials: RT
authors.lastname: Lopes
mesh_terms: D001938:Brazil; D003198:Computer Simulation; D017408:Guidelines as Topic; D006207:Half-Life; D007457:Iodine Radioisotopes / Q000032:analysis / Q000737:chemistry / Q000592:standards; D008345:Manganese / Q000032:analysis / Q000737:chemistry / Q000592:standards; D008631:Mercury Radioisotopes / Q000032:analysis / Q000737:chemistry / Q000592:standards; D008956:Models, Chemical; D011829:Radiation Dosage; D011868:Radioisotopes / Q000032:analysis* / Q000737:chemistry / Q000592:standards*; D011874:Radiometry / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007457:Iodine Radioisotopes; D008631:Mercury Radioisotopes; D011868:Radioisotopes; D008345:Manganese