Ultrasensitive Detection of Actinides by Accelerator Mass Spectrometry

Ultrasensitive Detection of Actinides by Accelerator Mass Spectrometry

Rugel, G.; Akhmadaliev, S.; Merchel, S.; Pavetich, S.

Accelerator mass spectrometry (AMS) represents an ultrasensitive technique for quantifying long-lived radionuclides. The new AMS facility DREAMS (DREsden AMS) see fig. 1 will broaden the spectrum of measurable radionuclides like 10Be, 26Al, 36Cl, 41Ca [1] to actinides with the setup of a new time-of-flight (TOF) beam line.
AMS is capable of quantifying isotope ratios, i.e. stable nuclides are usually measured in Faraday-cups while radionuclides are counted by detectors like an ionization chamber. In comparison to α-spectrometry a relative simple chemical sample preparation can be applied and isotopes like 239Pu and 240Pu can be distinguished at the detector. AMS determines ratios as low as 10-16, thus, providing the lowest detection limit of all mass spectrometry methods [2]. For long half-lives it is also more sensitive than decay counting techniques.
We expect about 100 events in the detector for samples containing an amount of about 104 to 106 atoms of the radionuclide in the ion source. As an example the sensitivity limit for a 236U/U ratio is about 10-12 [3].
This high sensitivity allows many applications from nuclear forensics, radiation protection, environmental monitoring to astrophysics. Isotopes measured by AMS are e.g. 236U, 237Np, 239,240,241,242,244Pu [3].
This setup will be also used in the future analyzing geological samples with high lateral resolution – without chemical sample preparation - a so called Super-SIMS – a combination of a SIMS (Secondary Ion Mass Spectrometry) with an accelerator.

[1] Akhmadaliev, S. et al. (2012) Nucl. Instr. and Meth. in Phys. Res. B, 6 pages, doi: 10.1016/j.nimb.2012.01.053.
[2] Fifield, L.K. (2008) Quaternary Geochronology 3, 276-290.
[3] Steier, P. et al. (2010) Nucl. Instr. and Meth. in Phys. Res. B 268,1045-1049

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Related publications

  • Poster
    International Workshop on Advanced Techniques in Actinide Spectroscopy (ATAS), 05.-07.11.2012, Dresden, Deutschland

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