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Primary standardization of Ra-224 activity by liquid scintillation counting



Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Lizbeth Laureano-Perez, Ronald Colle, Leticia S. Pibida, Elisa Napoli


A standard for 224Ra activity has been developed, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. The standard was confirmed by efficiency tracing and 4παβ(LS)-γ(NaI(Tl)) anticoincidence counting, as well as by 4πγ ionization chamber and NaI(Tl) measurements. Secondary standard ionization chambers were calibrated with an expanded uncertainty of 0.57 % (k = 2). Calibration settings were also determined for a 5 mL flame- sealed ampoule on several commercial reentrant ionization chambers (dose calibrators).
Applied Radiation and Isotopes


TDCR, liquid scintillation, anticoincidence counting, efficiency tracing, alpha therapy, activity calibration
Created October 11, 2019, Updated March 12, 2020