1. Alpha spectrometric evaluation of SRM-995 as a potential uranium/thorium double tracer system for age-dating uranium materials.
- Author
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Stanley, F., Glover, S., Stalcup, A., Spitz, H., and Beals, Donna
- Subjects
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ALPHA ray spectrometry , *URANIUM isotopes , *THORIUM isotopes , *RADIOACTIVE tracers , *URANIUM-thorium dating , *RADIOCHEMISTRY , *CHEMICAL purification , *ION exchange (Chemistry) - Abstract
Uranium-233 ( t ~ 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a U standard reference material (SRM-995) as a dual tracer system based on the in-growth of Th ( t ~ 7.34E3 years) for ~35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The Th/U atom ratio for SRM-995 was found to be 1.598E−4 (±4.50 %) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified ~36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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