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Published on: August 8, 2014
A new primary standardization of 229Th
R Fitzgerald1, R Collé, L Laureano-Pérez
1Physics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. ryan.fitzgerald@nist.gov
Abstract:
The National Institute of Standards and Technology (NIST) has certified a high-purity (229)Th Standard Reference Material as SRM 4328C, based on live-timed 4pialphabeta-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.
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