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Primary standardization of 212Pb activity by liquid scintillation counting



Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Lizbeth Laureano-Perez, Leticia Pibida, Brian E. Zimmerman


An activity standard for 212Pb in equilibrium with its progeny was realized, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. A Monte Carlo-based approach to estimating uncertainties due to nuclear decay data (branching ratios, beta endpoint energies, γ-ray energies, and conversion coefficients for 212Pb and 208Tl) led to combined standard uncertainties ≤ 0.20 %. Confirmatory primary measurements were made by LS efficiency tracing with tritium and 4παβ(LS)-γ(NaI(Tl)) anticoincidence counting. The standard is discussed in relation to current approaches to 212Pb activity calibration. In particular, potential biases encountered when using inappropriate radionuclide calibrator settings are discussed.
Applied Radiation and Isotopes


Pb-212, targeted alpha therapy, theranostic, TDCR, anticoincidence counting, efficiency tracing, radionuclide calibrator, dose calibrator, well counter, activity calibration, decay chain


Bergeron, D. , Cessna, J. , Fitzgerald, R. , Laureano-Perez, L. , Pibida, L. and Zimmerman, B. (2022), Primary standardization of 212Pb activity by liquid scintillation counting, Applied Radiation and Isotopes, [online],, (Accessed April 18, 2024)
Created September 22, 2022, Updated November 29, 2022