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A New Primary Standardization of Th-229



Ryan P. Fitzgerald, Lizbeth Laureano-Perez, Michelle M. Hammond, Leticia S. Pibida, Svetlana Nour, Brian E. Zimmerman


The National Institute of Standards and Technology (NIST) has certified a high-purity Th-229 Standard Reference Material as SRM 4328C, based on live-timed 4-pi alpha,beta-gamma anticoincidence counting (LTAC) of the equilibrium solution. The LTAC system was optimized to minimize the uncertainty in the result due to the two short-lived ground-states present in the decay chain. Confirmatory measurements were carried out by four other methods. Furthermore, the present absolute activity and measured gamma-ray emission rates were combined to obtain gamma-ray emission probabilities.
Applied Radiation and Isotopes


mass spectrometry standard, primary standard, radioactivity, tracer, Th-229


Fitzgerald, R. , Laureano-Perez, L. , Hammond, M. , Pibida, L. , Nour, S. and Zimmerman, B. (2010), A New Primary Standardization of Th-229, Applied Radiation and Isotopes (Accessed June 16, 2024)


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Created January 7, 2010, Updated February 19, 2017