Preparation and calibration of a 231Pa reference material
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A 231Pa reference material has been characterized for amount of protactinium. This reference material is primarily intended for calibration of 233Pa tracers produced for 235U–231Pa model age measurements associated with nuclear forensics and nuclear safeguards. Primary measurements for characterization were made by isotope dilution mass spectrometry of a purified 231Pa solution using a 233Pa isotopic spike. The spike was calibrated by allowing multiple aliquots of the 233Pa spike solution to decay to 233U and then measuring the ingrown 233U by isotope dilution mass spectrometry using a certified uranium assay and isotopic standard as a reverse-spike. The new 231Pa reference material will simplify calibration of the 233Pa isotope dilution spikes, provide metrological traceability, and potentially reduce the overall measurement uncertainty of model ages.
KeywordsIsotope dilution mass spectrometry Nuclear forensics 231Pa 233Pa Radiochronometry Reference material
Roger Henderson at LLNL performed the initial purification of the 231Pa that was used as the starting material for this project. His expertise and assistance is gratefully acknowledged. Funding for project activities at LLNL and at NIST was provided by the United Stated Department of Homeland Security. Analyses performed at NRC and NPL were internally funded.
Compliance with ethical standards
Conflict of interest
All authors declare that they have no conflict of interest.
Human and animal rights
This article does not contain any studies with human or animal subjects performed by the any of the authors.
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