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Updated: May 4, 2026

Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride
Published on: July 8, 2021
Primary activity standardization of ⁹⁹Tc by three different absolute methods
Paulo A L da Cruz1, Carlos J da Silva1, Denise S Moreira1
1Laboratório 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.
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.
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