Thermal ionization mass spectrometry of uranium with electrodeposition as a loading technique

Rokop, D.J.; Perrin, R.E.; Knobeloch, G.W.; Armijo, V.M.; Shields, William R.

doi:10.1021/ac00243a027

Cited by 38 publications

(23 citation statements)

References 16 publications

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“…Highest precisions in isotope ratio analysis are traditionally reported using MC-TIMS instruments, with relative standard deviations as low as 0.01% or better [107,186]. Various methods have been developed to enhance the total/ionization efficiency (and thus the detection limit and precision) of TIMS, e.g., using carbon additives, benzene gas, and resin bead loads [110,[145][146][147]178], or platinum coating and electrodeposition [148]. These methods aim to reduce the formation of oxides, improve beam focus and ion transmission by reducing the spatial extent of the sample load, or enhance the work function of the ionizer materials (usually rhenium, tantalum, tungsten or platinum).…”

Section: Introductionmentioning

confidence: 99%

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

Bürger

Riciputi

Bostick

et al. 2009

International Journal of Mass Spectrometry

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Section: Introductionmentioning

confidence: 99%

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

Bürger

Riciputi

Bostick

et al. 2009

International Journal of Mass Spectrometry

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“…The data show that the average U concentration in the eight samples is 56.5% by weight. All the samples show depletions in 235 U, the lowest value being sample 9.28 with an abundance of 0.559 as compared to the natural terrestrial value of 0.719 AE 0.003, which is the average value of nine replicate analyses of NBS/NIST 960, measured under the same mass spectrometric conditions using TIMS (Rokop et al, 1982).…”

Section: A Nuclear Parameters Of Reactor Zonementioning

confidence: 87%

The role of mass spectrometry to study the Oklo–Bangombé natural reactors

Laeter

Hidaka

2007

Mass Spectrometry Reviews

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The discovery of the existence of chain reactions at the Oklo natural reactors in Gabon, Central Africa in 1972 was a triumph for the accuracy of mass spectrometric measurements, in that a 0.5% anomaly in the (235)U/(238)U ratio of certain U ore samples indicated a depletion in (235)U. Mass spectrometric techniques thereafter played a dominant role in determining the nuclear parameters of the reactor zones themselves, and in deciphering the geochemical characteristics of various elements in the U-rich ore and in the surrounding rock strata. The variations in the isotopic composition of a large number of elements, caused by a combination of nuclear fission, neutron capture and radioactive decay, provide a powerful tool for investigating this unique geological environment. Mass spectrometry can be used to measure the present-day elemental and isotopic abundances of numerous elements, so as to decipher the past history of the reactors and examine the retentivity/mobility of these elements. Many of the fission products have a radioactive decay history that have been used to date the age and duration of the reactor zones, and to provide insight into their nuclear and geochemical behavior as a function of time. The Oklo fission reactors and their near neighbor at Bangombé, some 30 km to the south-east of Oklo, are unique in that not only did they become critical some 2 x 10(9) years ago, but also the deposits have been preserved over this period of geological time. The long-term geochemical behavior of actinides and fission products have been extensively studied by a variety of mass spectrometric techniques over the past 30 years to provide us with significant information on the mobility/retentivity of this material in a natural geological repository. The Oklo-Bangombé natural reactors are therefore geological analogs that can be evaluated in terms of possible radioactive waste containment sites. As more reactor zones were discovered, it was realized that they could be classified into two groups according to their burial depth in the Oklo mine-site. Reactor Zones 10, 13, and 16 were buried more deeply, and were therefore less weathered than the other zones. The less-weathered zones are of great importance in mobility/retentivity studies and therefore to the question of radioactive waste containment. Isotopic studies of these natural reactors are also of value in physics to examine possible variations in fundamental constants over the past 2 billion years.

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“…The overall efficiency can also be improved by using resin bead loading or electroplating instead of liquid-drop loading. 11,34,36 In special applications such as fission-track TIMS or zircon evaporation TIMS, micrometre-size particles are loaded directly onto a filament instead of dissolving each particle and using liquid-drop loading. 37,38 Thermal (surface) ionisation sources are utilised for the chemical analysis of aerosol particles, gases and organic compounds, but usually in combination with time-of-flight, quadrupole or other mass analysers that permit a fast scanning of the entire mass spectrum.…”

Section: Ion Sourcementioning

confidence: 99%

Thermal Ionisation Mass Spectrometry

Bürger

Vogl

Klötzli

et al. 2014

Sector Field Mass Spectrometry for Elemental and Isotopic Analysis

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The principle of TIMS is based on the formation of atom ions on a heated filament and the separation of these ions according to their mass/charge ratio in a mass spectrometer. In general, TIMS is applied for highprecision measurements of isotope ratios. In the basic design of a modern thermal ionisation source, a surface material is used in the shape of a flat ribbon filament. Usually, a solution (separated from the matrix and containing the element of interest in high concentration) is deposited in the centre of the filament as a liquid. Applying a current to the filament will evaporate and ionise the analyte deposited on the filament. In the case of a single-filament geometry, evaporation and ionisation of the analyte is accomplished with one filament, whereas in a double filament design, evaporation and ionisation is performed on two filaments placed parallel to each other. The analyte is evaporated on one filament, with ionisation occurring when the evaporated atoms strike the ionisation filament. A magnetic sector field is used as mass separator.

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Thermal ionization mass spectrometry of uranium with electrodeposition as a loading technique

Cited by 38 publications

References 16 publications

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

The role of mass spectrometry to study the Oklo–Bangombé natural reactors

Thermal Ionisation Mass Spectrometry

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