The Use of SIMS and SEM for the Characterization of Individual Particles with a Matrix Originating from a Nuclear Weapon.

Research output: Contribution to journalArticle


The application of scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) for characterization of mixed plutonium and uranium particles from nuclear weapons material is presented. The particles originated from the so-called Thule accident in Greenland in 1968. Morphological properties have been studied by SEM and two groups were identified: a “popcorn” structure and a spongy structure. The same technique, coupled with an energy-dispersive X-ray (EDX) spectrometer, showed a heterogeneous composition of Pu and U in the surface layers of the particles. The SIMS depth profiles revealed a varying isotopic composition indicating a heterogeneous mixture of Pu and U in the original nuclear weapons material itself. The depth distributions agree with synchrotron-radiation-based [mu]-XRF (X-ray fluorescence microprobe) measurements on the particle (Eriksson, M., Wegryzynek, D., Simon, R., & Chinea-Cano, E., in prep.) when a SIMS relative sensitivity factor for Pu to U of 6 is assumed. Different SIMS identified isotopic ratio groups are presented, and the influence of interferences in the Pu and U mass range are estimated. The study found that the materials are a mixture of highly enriched <sup>235</sup>U (<sup>235</sup>U:<sup>238</sup>U ratio from 0.96 to 1.4) and so-called weapons grade Pu (<sup>240</sup>Pu:<sup>239</sup>Pu ratio from 0.028 to 0.059) and confirms earlier work reported in the literature.


  • Ylva Ranebo
  • Mats Eriksson
  • Gabriele Tamborini
  • Nedialka Niagolova
  • Olivier Bildstein
  • Maria Betti
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Radiology, Nuclear Medicine and Medical Imaging


  • environmental radioactive particles, SIMS, uranium, Thule, SEM, plutonium, weapons grade enrichment, isotopic ratios
Original languageEnglish
Pages (from-to)179-190
JournalMicroscopy and Microanalysis
Issue number3
Publication statusPublished - 2007
Publication categoryResearch

Related research output

Ylva Ranebo, 2009, Lund University (Media-Tryck). 62 p.

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