Nucleogenic 36Cl, 236U and 239Pu in uranium ores

K. M. Wilcken*, L. K. Fifield, T. T. Barrows, S. G. Tims, L. G. Gladkis

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review


    The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments via neutron capture of thermal and epithermal neutrons. Concentrations are, however, very low and accelerator mass spectrometry (AMS) is required for quantitative measurements. A particular challenge is presented by the measurement of 236U/238U ratios down to the level of 10-13 that is expected from rocks with low uranium concentration. Here, we present the AMS methodology that has been developed at the ANU for measuring 236U/238U ratios at this level. The more established methodologies for 36Cl and 239Pu measurements are also summarised. These capabilities are then used to characterize the 36Cl, 236U and 239Pu concentrations in a range of uranium ores. A simple model of the neutron production and capture processes in subsurface environments has been developed and is presented. It is shown that nucleogenic 36Cl, 236U and 239Pu can be used to determine both thermal and epithermal neutron fluxes in subsurface environments. Potential applications include uranium exploration and monitoring of the environmental impact of uranium mining.

    Original languageEnglish
    Pages (from-to)3614-3624
    Number of pages11
    JournalNuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
    Issue number16
    Publication statusPublished - 1 Aug 2008


    • U
    • Pu
    • Cl
    • AMS
    • Nucleogenic isotope production
    • Uranium ore


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