The application of abundance sensitivity filters to the precise and accurate measurement of uranium series nuclides by plasma mass spectrometry

TitleThe application of abundance sensitivity filters to the precise and accurate measurement of uranium series nuclides by plasma mass spectrometry
Publication TypeJournal Article
Year of Publication2019
AuthorsScott S.R, Sims K.WW, Reagan M.K, Ball L., Schwieters J.B, Bouman C., Lloyd N.S, Waters C.L, Standish J.J, Tollstrup D.L
JournalInternational Journal of Mass Spectrometry
Volume435
Pagination321-332
Date Published2019/01
Type of ArticleArticle
ISBN Number1387-3806
Accession NumberWOS:000453773300041
KeywordsAbundance sensitivity; inductively-coupled plasma; isotope ratio measurements; juan-de-fuca; Lead-210; magma formation; MC-ICPMS; midocean; off-axis; physics; quadrupole; ra-226-th-230-u-238 disequilibria; radium; Retarding potential; ridges; spectroscopy; th-pa-ra; Thorium; time-scales; U-series; uranium; Uranium-series; volcanism
Abstract

Application of retardation filters has revolutionized the use of multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) for the measurement of U-series disequilibria. Here, we present an evaluation of the application of retardation energy filters coupled with ion counting detectors for the measurement of U-series disequilibria by MC-ICPMS. We show that: 1) The RPQ minimizes backgrounds caused by ions experiencing irregular flight paths at high masses of uranium series nuclides. This reduced background is important for low count rate measurements and has enabled us to develop an improved method for the determination of Ra-226/Ra-228 ratios using a dual SEM/RPQ collector block. 2) Systematic biases exist for isotope ratios of U-234/U-238 and Th-230/Th-232 without the use of RPQs; thus, the RPQ is important for measurement of both of these isotope ratios. 3) That the RPQ makes possible Pb-210 measurements in geologic samples using MC-ICPMS, but that this application is limited to samples that have low common Pb, such as carbonates and silica sinter. Additionally, we present mass spectrometric and gamma counting data for U-Th-Ra disequilibria in rock standard reference materials including AGV-2, AThO, BCR-1, BCR-2, BHVO-2, BIR-1a, DTS-1, PCC-1, RGM-2, TML, and W-2a. Comparing this new data with values from published literature enables us to provide consensus or recommended values for U, Th, and Ra-226 concentrations and Th-230/Th-232 ratios for each of these standards. We note that this is the first compilation of recommended radium concentrations for rock standard reference materials. (C) 2018 Elsevier B.V. All rights reserved.

DOI10.1016/j.ijms.2018.11.011
Short TitleInt. J. Mass Spectrom.
Student Publication: 
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