235U–231Pa age dating of uranium materials for nuclear forensic investigations
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Here, age dating of nuclear material can provide insight into source and suspected use in nuclear forensic investigations. We report here a method for the determination of the date of most recent chemical purification for uranium materials using the 235U-231Pa chronometer. Protactinium is separated from uranium and neptunium matrices using anion exchange resin, followed by sorption of Pa to an SiO2 medium. The concentration of 231Pa is measured by isotope dilution mass spectrometry using 233Pa spikes prepared from an aliquot of 237Np and calibrated in-house using the rock standard Table Mountain Latite and the uranium isotopic standard U100. Combined uncertainties of age dates using this method are 1.5 to 3.5 %, an improvement over alpha spectrometry measurement methods. Model ages of five uranium standard reference materials are presented; all standards have concordant 235U-231Pa and 234U-230Th model ages.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1224943
- Report Number(s):
- LLNL-JRNL-615952; JASPE2
- Journal Information:
- Journal of Analytical Atomic Spectrometry, Vol. 28, Issue 5; ISSN 0267-9477
- Publisher:
- Royal Society of Chemistry
- Country of Publication:
- United States
- Language:
- English
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