Measurements of the ruthenium isotopic composition of nuclear samples could provide information about the method of sample production, sample irradiation history, and age. To investigate the feasibility and applicability of this idea, this study focuses on measurements of the ruthenium isotope composition of a nominally single-isotope Ru radioactivity standard, where the complications of environmental mixing are eliminated. The measurements of the Ru standards reveal unusual stable ruthenium isotopic compositions consistent with fissiogenic ruthenium.
View Article and Find Full Text PDFA highly-enriched Pu isotope dilution reference material has been prepared and characterized for metrologically traceable measurements of very small quantities of plutonium. The amount of plutonium in samples associated with nuclear safeguards and nuclear forensic measurements can be significantly less than 1 ng. Accordingly, the ability to quantify the amount and isotopic composition of plutonium from a single mass-spectrometric analysis is particularly desirable.
View Article and Find Full Text PDFJ Radioanal Nucl Chem
January 2018
A new determination of the Th half-life was made based on measurements of the Th massic activity of a high-purity solution for which the Th molality had previously been measured. The Th massic activity was measured by direct comparison with SRM 4328C using 4παβ liquid scintillation counting, NaI counting, and standard addition liquid scintillation counting. The massic activity was confirmed by isotope dilution alpha spectrometry measurements.
View Article and Find Full Text PDFCompositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. Using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclides generated during the explosion.
View Article and Find Full Text PDFA new reference material was characterized for Th molality and thorium isotope amount ratios. This reference material is intended for use in nuclear forensic analyses as an isotope dilution mass spectrometry spike. The reference material value and expanded uncertainty (k = 2) for the Th molality is (1.
View Article and Find Full Text PDFThis paper describes an approach to measuring extinct fission products that would allow for the characterization of a nuclear test at any time. The isotopic composition of molybdenum in five samples of glassy debris from the 1945 Trinity nuclear test has been measured. Nonnatural molybdenum isotopic compositions were observed, reflecting an input from the decay of the short-lived fission products (95)Zr and (97)Zr.
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