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Activity standard and calibrations for 227Th with ingrowing progeny



Denis E. Bergeron, Jeffrey T. Cessna, Brittany Broder, Leticia Pibida, Ryan P. Fitzgerald, Morgan DiGiorgio, Elisa Napoli, Brian E. Zimmerman


Thorium-227 was separated from its progeny and standardized for activity by the triple-to-double coincidence ratio (TDCR) method of liquid scintillation counting. Confirmatory liquid scintillation-based measurements were made using efficiency tracing with 3H and live-timed anticoincidence counting (LTAC). The separation time and the efficiency of the separation were confirmed by gamma-ray spectrometry. Calibrations for reentrant pressurized ionization chambers, including commercial radionuclide calibrators, and a well-type NaI(Tl) detector are discussed.
Applied Radiation and Isotopes


Th-227, Ra-223, primary standard, decay chain, progeny ingrowth, dose calibrator, gamma counter, decay data, targeted alpha therapy, precision medicine, administered activity


Bergeron, D. , Cessna, J. , Broder, B. , Pibida, L. , Fitzgerald, R. , DiGiorgio, M. , Napoli, E. and Zimmerman, B. (2024), Activity standard and calibrations for 227Th with ingrowing progeny, Applied Radiation and Isotopes, [online],, (Accessed May 19, 2024)


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Created April 20, 2024, Updated May 14, 2024