First experimental evidence by SIMS of different surface binding energies for uranium according to its oxidation state

Desgranges, Lionel; Pasquet, B.; Roure, I.

doi:10.1016/j.apsusc.2011.02.039

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…The other spectrum (dash line) adopts a similar profile but with a significant increase in the intensity around 70–80 eV. As described in a previous paper, this feature is considered to be the signature of an oxidation effect on uranium.…”

Section: Resultssupporting

confidence: 53%

“…Uranium energy spectra measured during the sputtering of unirradiated UO 2 samples exhibit one or two peaks as a function of the surface oxidation state. We recently demonstrated that the relative intensity of these peaks can be related to the uranium oxidation state at the surface . This theoretical result was obtained on UO 2 single crystals whereas current UO 2 nuclear fuel is polycrystalline.…”

Section: Introductionmentioning

confidence: 85%

“…. The intensity of the difference curve is then normalised by the measured intensity to calculate a ratio that quantitatively characterises the oxidation state of the analysed area . Using this procedure, it is already clear that the energy spectrum measured on two grains, as shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

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Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Roure

Pasquet

Desgranges

et al. 2012

Surface & Interface Analysis

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The energy spectrum of uranium in irradiated fuels is known to give key information on the oxidation state of uranium at the sample surface. In this respect, it is essential to know the operating conditions applied to measure energy spectra by secondary ion mass spectrometry in order to obtain reliable data. Using a focussed beam on CAMECA IMS6f, the acquisition of an energy spectrum is performed along a line on the sample surface because the primary beam position moves as a function of the high voltage. Depending on the size of UO 2 grains, the analysed area can be limited within one single grain or spread among many grains. The consequences of such acquisition conditions are discussed in this paper.

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Section: Resultssupporting

confidence: 53%

Section: Introductionmentioning

confidence: 85%

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Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Roure

Pasquet

Desgranges

et al. 2012

Surface & Interface Analysis

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“…The mass spectra were obtained by scanning the magnet and measuring the ion counts as a function of mass-to-charge ratio. A representative mass spectrum of the corrosion layer is shown in Fig 2. This mass spectrum, representing a mass range from 230 to 280 amu, was selected to encompass U + , UO + and UO 2 + ions typically seen in analysis of uranium containing materials [19,20]. The first important observation is that the initial radiometric counting performed on this sample did not yield any detectable uranium signals, contrary to the SIMS analysis where ion signals from uranium isotopes ( 235 U + , 238 U + ) and uranium-containing compounds (UO + , UF + , UO 2 + and UOF + ) were found.…”

Section: Resultsmentioning

confidence: 99%

Secondary ion mass spectrometry signatures for verifying declarations of fissile‐material production

Willingham

Naes

Burns

et al. 2015

Applied Radiation and Isotopes

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Direct analysis of uranium enrichment facility components were performed using secondary ion mass spectrometry (SIMS). A standard protocol was developed to enable preparation of SIMS samples from a corroded pipe piece without disturbing the corrosion layer. Unique uranium, oxygen and fluorine containing signatures were discovered in the corrosion layer by performing a mass scan of the region of interest from 230 to 280amu. These signatures identified the source of the corrosion layer as uranium hexafluoride (UF6) or an associated hydrolysis product. Isotopic analysis of the corrosion layer determined enrichment of (235)U to a value of 0.0116±0.0019 for the (235)U/(238)U isotopic ratio as compared to the NIST traceable standard (CRM 112-A) with a natural (235)U/(238)U isotopic ratio of 0.007254±0.000004. SIMS depth analysis revealed that the corrosion layer was isotopically homogenous to a depth of ~23.5µm. Optical profilometry measurements prior to and following SIMS depth analysis were used to determine a sputter rate of 0.48nm/s for 18.5keV O(-) ion bombardment of the corrosion layer. The data presented is conclusive evidence that SIMS depth analysis can be used to identify novel nuclear archeology signatures from uranium enrichment components and perform meaningful isotopic analysis of these signatures.

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“…This is why we decided to focus on the uranium energy spectrum. We recently demonstrated that the relative intensity of the two peaks appearing in the unirradiated UO 2 energy spectra as a function of oxygen flooding can be related to the uranium oxidation state of the surface . Thus, in theory, energy spectrum measurements could also be used to characterise the oxidation state of irradiated UO 2 .…”

Section: Introductionmentioning

confidence: 99%

Changes in uranium energy spectra measured by SIMS on slightly hyper‐stoichiometric UO₂

Desgranges

Pasquet

Roure

et al. 2012

Surface & Interface Analysis

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The energy spectra of UO 2 samples with slight hyper-stoichiometry were measured. In addition to the regular peak detected at 20 eV, it was observed that another peak at 80 eV would grow with the increasing stoichiometry. The relative intensities of the two peaks were used to determine the surface O/U ratio of the sample. We discuss how it would be possible to determine bulk O/U ratio from these results.

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First experimental evidence by SIMS of different surface binding energies for uranium according to its oxidation state

Cited by 7 publications

References 16 publications

Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Secondary ion mass spectrometry signatures for verifying declarations of fissile‐material production

Changes in uranium energy spectra measured by SIMS on slightly hyper‐stoichiometric UO₂

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First experimental evidence by SIMS of different surface binding energies for uranium according to its oxidation state

Cited by 7 publications

References 16 publications

Measurement of energy spectra on irradiated polycrystalline UO2 samples using secondary ion mass spectrometry

Measurement of energy spectra on irradiated polycrystalline UO2 samples using secondary ion mass spectrometry

Secondary ion mass spectrometry signatures for verifying declarations of fissile‐material production

Changes in uranium energy spectra measured by SIMS on slightly hyper‐stoichiometric UO2

Contact Info

Product

Resources

About

Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Measurement of energy spectra on irradiated polycrystalline UO₂ samples using secondary ion mass spectrometry

Changes in uranium energy spectra measured by SIMS on slightly hyper‐stoichiometric UO₂