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Antoine, Monaco

Ranebo Y.,Lund University | Ranebo Y.,European Commission | Pollanen R.,Radiation and Nuclear Safety Authority | Eriksson M.,IAEA MEL | And 2 more authors.
Applied Radiation and Isotopes

Spherical particles with known properties were used to demonstrate and test a novel software package known as AASIFIT, which is able to unfold complex alpha spectra. A unique feature of the program is that it uses simulated peak shapes in the fitting process. The experimental reference particles in the testing were artificially produced U particles of diameter 1.4μm and a nuclear bomb particle with a twenty-fold greater diameter, mainly composed of U and Pu dioxides. AASIFIT was used to determine the density of the U particles. In addition, the activities of 239+240Pu and 241Am were determined for the nuclear bomb particle and compared to earlier determinations in the literature. The results of this investigation demonstrated that the software can be used to estimate the properties of particles emitting alpha radiation. However, the composition and geometry of the investigated particles need to be known with good accuracy for reliable estimates. Furthermore, uncertainties in the stopping power data, especially for U and Pu, may have an influence on the results obtained from the software. © 2010 Elsevier Ltd. Source

Jimenez-Ramos M.C.,University of Seville | Garcia Lopez J.,University of Seville | Eriksson M.,IAEA MEL | Jernstrom J.,Technical University of Denmark | Garcia-Tenorio R.,University of Seville
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

Transuranic nuclides have been released into the environment since the beginning of the nuclear age. In many of the areas so contaminated, a significant fraction of the plutonium appears under the form of radioactive particles (also called 'hot' particles). In previous works, García López et al. (2007) [1] and Jiménez-Ramos et al. (2010) [2], radioactive particles from aircraft accidents in Palomares and Thule have been characterized. Using micro-Proton Induced X-ray Emission (μ-PIXE) and confocal X-ray fluorescence microprobe (μ-XRF), the L-lines of the main components in these particles, U and Pu, were analyzed. In this work, the key goal is the possibility to determine elemental ratios and concentration of transuranic elements in hot particles from the same areas but using their K-lines, because of their advantages in comparison with the study of L-lines. Indeed, the U and Pu K-lines present not overlapping between the main peaks in the spectra and the X-ray absorption in the sample is much lower than for L-lines. © 2011 Elsevier B.V. All rights reserved. Source

Ranebo Y.,European Commission | Ranebo Y.,Lund University | Niagolova N.,European Commission | Erdmann N.,European Commission | And 3 more authors.
Analytical Chemistry

In order to prevent nuclear proliferation, the isotopic analysis of uranium and plutonium microparticles has strengthened the means in international safeguards for detecting undeclared nuclear activities. In order to ensure accuracy and precision in the analytical methodologies used, the instrumental techniques need to be calibrated. The objective of this study was to produce and characterize particles consisting of U, Pu, and mixed U-Pu, suitable for such reliability verifications. A TSI vibrating orifice aerosol generator in connection with a furnace system was used to produce micrometer sized, monodispersed particles from reference U and Pu materials in solution. The particle masses (in the range of 3-6 pg) and sizes (∼1.5 μm) were controlled by the experimental conditions and the parameters for the aerosol generator. Size distributions were obtained from scanning electron microscopy, and energy-dispersive X-ray analysis confirmed that the particle composition agreed with the starting material used. A secondary ion mass spectrometer (SIMS) was used to characterize the isotopic composition of the particles. Isobaric and polyatomic interference in the SIMS spectra was identified. In order to obtain accurate estimates of the interference, a batch of Pu particles were produced of mainly 242Pu. These were used for SIMS analysis to characterize the relative ionization of Pu and U hydride ions and to determine the SIMS useful yields of U and Pu. It was found that U had a higher propensity to form the hydride than Pu. Useful yields were determined at a mass resolution of 450 for U-Pu particles: (1.71 ± 0.15) % for Pu and (0.72 ± 0.06) % for U. For Pu particles: (1.65 ± 0.14) % for Pu. This gave a relative sensitivity factor between U and Pu (RSFU:Pu) of 2.4 ± 0.2. However, the RSFU:Pu showed large fluctuations during the sputtering time for each analyses of the mixed U-Pu particles, in the range of 1.9-3.4. © 2010 American Chemical Society. Source

Holm E.,Norwegian Radiation Protection Authority | Eriksson M.,IAEA MEL | Lind B.,Norwegian Radiation Protection Authority | Levy I.,IAEA MEL | Kinn G.,Norwegian Radiation Protection Authority
Journal of Radioanalytical and Nuclear Chemistry

Electrodeposition is the major method for source preparation of actinides, Pu, Am, Th, U using stainless steel discs and spontaneous deposition for Polonium using discs of silver. Worldwide coins are manufactured of bronze, steel, copper plated steel, cupronickel, brass and alloys of Cu-Ni-Zn. The price of the coins which can be used have a value between 0.1 and 0.4 Euro considerably cheaper than electropolished stainless steel discs, 0.8 Euro. This investigation had the purpose to show the possibility to use coins from different countries for source preparation, the energy resolution and deposition efficiency. We obtained plating recoveries ranging from 50 to 100 % and the energy resolution varied between 21 and 75 keV for the different coins tested. © Akadémiai Kiadó, Budapest, Hungary 2012. Source

Jimenez-Ramos M.C.,University of Seville | Eriksson M.,IAEA MEL | Ranebo Y.,European Commission | Ranebo Y.,Lund University | And 4 more authors.
Spectrochimica Acta - Part B Atomic Spectroscopy

In order to validate and to gain confidence in two micro-beam techniques: particle induced X-ray emission with nuclear microprobe technique (μ-PIXE) and synchrotron radiation induced X-ray fluorescence in a confocal alignment (confocal SR μ-XRF) for characterization of microscopic particles containing actinide elements (mixed plutonium and uranium) a comparative study has been performed. Inter-comparison of the two techniques is essential as the X-ray production cross-sections for U and Pu are different for protons and photons and not well defined in the open literature, especially for Pu. The particles studied consisted of nuclear weapons material, and originate either in the so called Palomares accident in Spain, 1966 or in the Thule accident in Greenland, 1968. In the determination of the average Pu/U mass ratios (not corrected by self-absorption) in the analysed microscopic particles the results from both techniques show a very good agreement. In addition, the suitability of both techniques for the analysis with good resolution (down to a few μm) of the Pu/U distribution within the particles has been proved. The set of results obtained through both techniques has allowed gaining important information concerning the characterization of the remaining fissile material in the areas affected by the aircraft accidents. This type of information is essential for long-term impact assessments of contaminated sites. © 2010 Elsevier B.V. All rights reserved. Source

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