Evaluation strategies for isotope ratio measurements of single particles by LA-MC-ICPMS

Data evaluation is a crucial step when it comes to the determination of accurate and precise isotope ratios computed from transient signals measured by multi-collector–inductively coupled plasma mass spectrometry (MC-ICPMS) coupled to, for example, laser ablation (LA). In the present study, the applicability of different data evaluation strategies (i.e. ‘point-by-point’, ‘integration’ and ‘linear regression slope’ method) for the computation of (235)U/(238)U isotope ratios measured in single particles by LA-MC-ICPMS was investigated. The analyzed uranium oxide particles (i.e. 9073-01-B, CRM U010 and NUSIMEP-7 test samples), having sizes down to the sub-micrometre range, are certified with respect to their (235)U/(238)U isotopic signature, which enabled evaluation of the applied strategies with respect to precision and accuracy. The different strategies were also compared with respect to their expanded uncertainties. Even though the ‘point-by-point’ method proved to be superior, the other methods are advantageous, as they take weighted signal intensities into account. For the first time, the use of a ‘finite mixture model’ is presented for the determination of an unknown number of different U isotopic compositions of single particles present on the same planchet. The model uses an algorithm that determines the number of isotopic signatures by attributing individual data points to computed clusters. The (235)U/(238)U isotope ratios are then determined by means of the slopes of linear regressions estimated for each cluster. The model was successfully applied for the accurate determination of different (235)U/(238)U isotope ratios of particles deposited on the NUSIMEP-7 test samples. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-012-6674-3) contains supplementary material, which is available to authorized users

Contribution of an interlaboratory comparison to the certification of the stam/irmm-0243 243am spike reference material

International audienceFollowing the expression of the need for an americium (Am) standard and particularly for one with a certified americium 243 (243Am) content in 2009 and thereafter by the International Atomic Energy Agency, the Commissariat a l'Energie Atomique (CEA) et aux Energies Alternatives/ Direction de l'Energie Nucleaire of Marcoule and the Joint Research Center in Geel carried out a collaborative project for the production of a certified reference material enriched in 243Am. CEA's Commission d'ETAblissement des Methodes d'Analyse organized an interlaboratory comparison on this material prior to the issuing of its certificate. The usefulness of an interlaboratory comparison to assess the measurement capabilities in the field and to confirm the provisional certified values for the amount contents of 243Am, 241Am, total Am, the isotopic composition and the molar mass of Am has been demonstrated. Further this interlaboratory comparison enabled to derive an indicative value for the n(242mAm)/n(243Am) isotope amount ratio

Verification measurements of the IRMM-1027 and the IAEA large-sized dried (LSD) spikes

International audienceIn the frame of the accountancy measurements of the fissile materials, reliable determinations of the plutonium and uranium content in spent nuclear fuel are required to comply with international safeguards agreements. Large-sized dried (LSD) spikes of enriched 235U and 239Pu for isotope dilution mass spectrometry (IDMS) analysis are routinely applied in reprocessing plants for this purpose. A correct characterisation of these elements is a pre-requirement for achieving high accuracy in IDMS analyses. This paper will present the results of external verification measurements of such LSD spikes performed by the European Commission and the International Atomic Energy Agency

Interlaboratory comparison on 243Am reference material for nuclear safeguards and security

International audienc

243Am certified reference material for nuclear safeguards and security

International audienc