| Autor: |
Middendorp, Ronald, Knott, Alexander, Dürr, Martin |
| Jazyk: |
angličtina |
| Rok vydání: |
2014 |
| Zdroj: |
Advanced Techniques in Actinide Spectroscopy 2014, Dresden-Rossendorf, Germany, 2014-11-03-2014-11-07 |
| Popis: |
For the determination of isotope ratios, mass spectrometry represents the predominant measurement method capable of reaching a high sensitivity at the same time providing results with high accuracy and precision. The application of analytical procedures involves calibration and tests to assure high quality measurements. To this end, test objects with known properties are used as a standard, e.g. ref-erence materials provided by national institutions or commercial providers. Some reference materials are customized for specific analytical procedures, e.g. with properties matched to typical measurement samples.Isotopic ratio determination of micrometer-sized parti-cles is a tool used for nuclear safeguards by the Interna-tional Atomic Energy Agency (IAEA) in order to verify the non-proliferation obligations of states signatory to the Non-Proliferation Treaty. For example, uranium par-ticles are recovered from swipe samples and analyzed for the isotopic ratios of uranium isotopes in each indi-vidual particle [1]. Hereby signatures from processing of nuclear materials are revealed which provides a tool to detect possible clandestine activities. At the For-schungszentrum Jülich uniform (monodisperse) micro-particles consisting of uranium oxide are synthetically produced using a vibrating orifice aerosol generator (VOAG). The VOAG creates a stream of droplets iden-tical in size from a liquid feed consisting of a dilute ura-nyl-nitrate solution that has been prepared from a mate-rial with certified uranium isotope ratios [2]. The droplets are dried and calcinated yielding solid mi-cro-particles with a specific uranium elemental content per particle in the range of a few picograms and uranium isotope ratios as present in the liquid feed. The goal is to provide reference material for micro-analytical techniques, mainly for particle analysis with Large-Geometry Secondary Ion Mass Spectrometry and the so-called Fission Track Thermal Ionization Mass Spectrometry. These mass spectrometric techniques represent the state-of-the-art in the particle analysis for IAEA safeguards purposes.First uranium particles of approximately one micrometer diameter have been produced at For-schungszentrum Jülich (Figure 1) and are currently being analyzed with respect to size, morphology and homogeneity of these properties across the produced batch of particles. The production process based on an aerosol with uniform droplets should yield particles with specific elemental content and isotope ratio for each individual particle, which can be verified for a subsample of particles using iso-tope dilution mass spectrometry [3]. Further future work will study methods to produced micro-particles into a solid matrix for simplified handling, storage, transport and measurement. The produc-tion principle has the potential to provide particles that are suitable as certified reference material for micro-analytical methods on actinides in general. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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