Isotope analyses neodymium

Because seawater uptake dominates the REE content of metalliferous sediment, neodymium isotopic analysis of metalliferous carbonate can provide a reliable proxy for contemporaneous seawater, away from input of near-vent sulfide detritus (Mills et al., 1993). Osmium also exhibits a similar behavior and seawater dominates the isotopic composition of metalliferous sediments even close to active vent sites (Ravizza et al., 1996). Consequently, analysis of preserved metalliferous carbonate sediments has proven extremely useful in determining the past osmium isotopic composition of the oceans, both from modem marine sediments (e.g., Ravizza, 1993 Peucker-Ehrenbrink et al., 1995) and those preserved in ophiolites (e.g., Ravizza et al., 2001). Only in sediments close to an ultramafic-hosted hydrothermal system, have perturbations from a purely seawater osmium isotopic composition been observed (Cave et al., 2003, in press). 

Luais B, Telouk P, Albarede F (1997) Precise and accurate neodymium isotopic measurements by plasma-source mass spectrometry. Geochim Cosmochim Acta 61 4847-4854 Marechal C, Telouk P, Albarede F (1999) Precise analysis of copper and zinc isotopic compositions by plasma-source mass spectrometry. Chem Geol 156 251-273... 

Comparative studies of neodymium measurements in UOj fuel for the future application of local burn up calculations have been carried out by the SIMS analysis of a Nd implanted UOj single crystal. Samples for a round robin test were produced by the implantation of " Nd (5 x 10 ° at cm , 400 keV) in a UOj single crystal. Different depth profiles of the Nd "/ U+ ratio and especially the NdO /Nd, UO+/U+ and U02 /U+ ratios obtained by SIMS are not constant over time and indicate evidence of some fluctuations during the analysis. SIMS plays a dominant role for particle analysis, but also LA-ICP-MS with lower spatial resolution can be applied to identify anomalies in the isotopic composition of radionuclides. 

A full account of the problems considered in collecting, storing, and processing marine samples for transuranic analysis is given in the above-mentioned review (4). The specific methods discussed here were foimd effective at least for the transuranic analyses of seawater and sediments contaminated by global fallout, nuclear fuel reprocessing wastes, or nuclear power plant operation waste. In these cases, a preliminary acid treatment of the sample in the presence of suitable yield monitors seems to solubilize the transuranic elements and achieves isotopic equilibration between the yield monitor and sample. The yield monitors used were either Pu or sep qj. 238,239,240,24ip whereas Am was used for Am, 2 Cm, and by inference, Cf. In addition, it was convenient to use 50 mg of a lanthanide (neodymium) as a carrier for americium to purify the separated americium fraction. 

Malinowski J (1967) Precise determination of uranium in pure metal and uranium compounds by constant current coulometry Talanta 14 283 Marsh SF, Ortiz MR, Abernathey RM, Rein JE (1974) Improved 2-column ion exchange separation of plutonium, uranium and neodymium in mixed U/Pu fuels for burn up measurements, LA5568 Marsh SF, Abernathey RM, Rein JE (1981) Evaluation of treatments to attain isotopic equilibration of plutonium preceding the resin bead technique for mass spectrometric assay analysis of spent reactor fuel. In Minutes 4th SALE participants meeting, Argonne, p 218 Anal Lett 13 1487... 

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