Contribution of bulk mass spectrometry isotopic analysis to characterization of materials in the framework of CMX-4

Analytical considerations in the determination of uranium isotope ratios in solid uranium materials using laser ablation multi-collector ICP-MS

“…During CMX-4, organised by the International Technical Working Group on Nuclear Forensics (ITWG), two low-enriched UO 2 pellets were delivered to each participating laboratory [ 3 ]. After initial non-destructive analysis using high resolution gamma spectrometry [ 9 ], fragments of ∼1.3 g of these two UO 2 pellets were dissolved in 8 M HNO 3 and subsequently analysed for their U isotopic composition using TIMS, following accredited analytical procedures [ 5 ]. These TIMS results served as a basis for the comparison to the LA-MC-ICP-MS measurements.…”

“…As the two low-enriched UO 2 pellets CMX-4-9-1 and CMX-4-9-3 were part of the fourth Collaborative Materials Exercise (CMX-4), their U isotopic composition was also measured by the participating laboratories using either TIMS or ICP-MS [ 5 ] or gamma spectrometry [ 9 ]. These results, summarised recently [ 5 , 9 ], essentially confirm the U isotopic abundances reported here and as such present another independent check of the accuracy of the LA-MC-ICP-MS. Participating laboratories using TIMS or ICP-MS dissolved the UO 2 pellets, prior to any mass spectrometric measurement.…”

“…a fraction of the solid sample is dissolved in strong acids, followed by chemical separation of U from the sample matrix constituents [ 5 , 6 ]. The actual measurement step is conducted using either thermal ionisation mass spectrometry (TIMS), high-resolution ICP-OES [ 7 , 8 ], or any kind of ICP-MS instrumentation [ 5 , 6 ]. This analytical approach, especially in combination with TIMS, is well established and offers very accurate and precise results.…”

Fourth Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group

“…Within this special section, the reader will find major outcomes from CMX-4 contained within one of seven technical articles organized by technical area [10][11][12][13][14][15][16], and one additional article briefly describing the experiences of seven of the laboratories participating in the CMX series of exercises for the first time [17]. The latter chronicles the challenges these newcomers faced, from the receipt and handling of special nuclear materials, to the timely analysis and reporting of results under operational timelines-all made possible by transforming often ''general use'' radioanalytical laboratories to execute analytical plans and quality assurance/quality control processes of a sufficient rigor for a court of law.…”

“…However, more advanced, precise, accurate, expensive and tedious mass spectrometric techniques are often needed in instances where two or more nuclear materials are being compared and contrasted to each other for the purposes of group inclusion/exclusion to establish or reject connections between people, places, events and things. Kuchkin et al [13] summarizes several bulk mass spectrometric techniques that were applied by the exercise participants within 1-weeks' time during CMX-4. With few exceptions, these techniques have been shown [18] to provide more accurate and precise measurements with lower overall associated uncertainties of most longer-lived actinide isotopes than radiometric techniques like alpha spectrometry and HRGS.…”