Experimental investigation of the ionization mechanisms of uranium in thermal ionization mass spectrometry in the presence of carbon

Kraiem, M.; Mayer, Klaus; Gouder, T.; Seibert, Α.; Wiss, T.; Thiele, H.; Hiernaut, J.-P.

doi:10.1016/j.ijms.2009.10.001

Cited by 25 publications

(30 citation statements)

References 82 publications

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“…Analysis of the U4f region for the annealed sample after Ar + ion etching provided evidence to suggest the presence of a duplex oxide structure, consisting of a near stoichiometric dioxide outer layer with an oxy-carbide inter-layer between the dioxide and metal (Figure 3). The evolution of the peak in the U4f 7/2 region at (377.8 eV) and U4f 5/2 region (at 388.4 eV) in addition to the development of an additional peak in the C1s region (Figure 4, 281.8 eV) is similar to the heat induced formation of an oxycarbide (UO x C y ) as reported by Kraiem et al [12], Paul and Sherwood [13] and observed in the heat affected zone of welded uranium by Petherbridge et al [14]. The work of Orlov et al [15] would suggest the UO x C y sub layer was formed by the carbothermic segregation and reaction of bulk carbon impurities (ca 50 ppm) at the oxide metal interface.…”

Section: Surface Analysissupporting

confidence: 84%

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

et al. 2012

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The reaction kinetics of depleted uranium under constant hydrogen pressure (1 bar) have been measured as a function of reaction temperatures between 65 and 385 °C for as-polished and vacuum annealed samples. Enhanced hydrogen reactivity was observed on samples that underwent vacuum annealing prior to hydrogen exposure. The enhanced reactivity was found to be the result of enhanced nucleation rates on annealed samples since the specific rate per reacting unit area remained unaffected. X-ray photoelectron spectroscopy demonstrates that the nucleation kinetics were promoted on annealed samples as a result of the dehydration and partial reduction of the UO 2+x outer oxide layer and the formation of an oxycarbide (UO x C y ) sub-layer.

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Section: Surface Analysissupporting

confidence: 84%

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

et al. 2012

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“…Moreover, a special nuclear reactor with appropriate neutron spectrum and flux must be used to irradiate the samples, and micro‐sampling of particles for deposition onto the TIMS filaments has to be carried out. Furthermore, the TIMS technique has a measurement efficiency, defined as the ratio of the number of detected ions to the number of atoms in the sample, which typically ranges from 0.001% to 0.1% for uranium depending on the ionization source of the TIMS system . As a consequence, the detection and measurement of minor isotopes ( 234 U and 236 U) are difficult when the particles are sub‐micrometric and contain less than 1 fg of minor isotopes for natural uranium.…”

Section: Introductionmentioning

confidence: 99%

Determination of the isotopic composition of single sub‐micrometer‐sized uranium particles by laser ablation coupled with multi‐collector inductively coupled plasma mass spectrometry

Ronzani

Hubert

Pointurier

et al. 2019

Rapid Comm Mass Spectrometry

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Rationale A multi‐collector inductively coupled plasma (MC‐ICP) mass spectrometer coupled to a UV ns‐laser ablation (LA) system was used to measure uranium isotopic ratios (234U/238U, 235U/238U and 236U/238U) in single uranium particles of various sizes and isotopic compositions, including home‐made sub‐micrometric natural uranium particles of narrow size distribution (415 ± 60 nm). Methods The LA‐ICP mass spectrometer was operated in wet plasma conditions thanks to simultaneous injection of the laser aerosol and water vapor through a desolvating nebulizer. The isotopic ratios were corrected for mass bias and gain factors between detectors. The 236U/238U ratios were also corrected for the presence of 235U hydrides and tailing of the 238U+ peak. Results 236U/238U ratios were successfully measured in micrometer‐sized particles from the NBS U050 certified standard material with a 236U/238U ratio of ~5 × 10−4. The analysis of 77 natural uranium sub‐μm‐sized particles yielded a very good trueness with respect to the expected 234U/238U and 235U/238U ratios, while the measurement errors for single particles ranged from −2.7% to +2.1% for 235U/238U and from −17% to +33% for the 234U/238U ratios. Their relative combined standard uncertainties ranged from 3.3% to 32.8% and from 0.4% to 4.0% for 234U/238U and 235U/238U ratios, respectively. In addition, extremely low detection limits, in the attogram range, were achieved. Conclusions This study demonstrates that coupling of a ns‐laser ablation system with a MC‐ICP mass spectrometer allows measurements of the isotopic composition in natural uranium particles of a few hundreds of nm with very good trueness, average combined standard uncertainties of ~1% for 235U/238U ratios and 12% for 234U/238U ratios, and detections limits of a few ag for minor isotopes.

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“…UO + and UO 2 + ) that occurs before the filament surface is hot enough to dissociate the sample molecules and ionize the atoms. Recently, it has been proven [22] that upon heating under vacuum, carbon induces the sample to turn into a U-carbide compound in which formation of U + metal ions is promoted at the expense of the undesirable volatile oxide species. Thus, first investigations in this work focused on the enhancement of the ionization efficiency within measurements of diluted uranium solutions of IRMM isotope reference materials using carburized TIMS filaments.…”

Section: Introductionmentioning

confidence: 99%

Development of an improved method to perform single particle analysis by TIMS for nuclear safeguards

Kraiem

Stephan

Kühn

et al. 2011

Analytica Chimica Acta

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Experimental investigation of the ionization mechanisms of uranium in thermal ionization mass spectrometry in the presence of carbon

Cited by 25 publications

References 82 publications

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

Determination of the isotopic composition of single sub‐micrometer‐sized uranium particles by laser ablation coupled with multi‐collector inductively coupled plasma mass spectrometry

Development of an improved method to perform single particle analysis by TIMS for nuclear safeguards

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