Hostname: page-component-76fb5796d-x4r87 Total loading time: 0 Render date: 2024-04-27T02:39:58.620Z Has data issue: false hasContentIssue false
  • English
  • Français

Towards Achieving Low Background Levels in Routine Dating by Liquid Scintillation Spectrometry

Published online by Cambridge University Press:  18 July 2016

Alan G Hogg
Alan G Hogg*
Affiliation:
Waikato Radiocarbon Dating Laboratory, University of Waikato, Private Bag 3105, Hamilton, New Zealand. Email: alan.hogg@waikato.ac.nz.
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

International radiocarbon intercalibration studies have revealed that radiometric laboratories using liquid scintillation (LS) spectrometry of benzene reported, on average, younger ages for near-background standards than either gas proportional counter (GPC) or accelerator mass spectrometry (AMS) laboratories. These studies suggested that the younger LS ages are probably related to the use of spectrophotometric benzene as a background standard. An analysis of successive 110-ka subfossil wood (Airedale Reef Ancient Wood: ARAW) standards shows that vacuum line memory effects occur in LS spectrometry and, consequently, must be corrected to obtain accurate 14C dates. ARAW standards, measured at monthly intervals in the Waikato laboratory, are used to provide blank corrections for both research and routine dating applications. The strong correlation between the ARAW δ14C data and the sample activities that preceded the standards may provide an opportunity to obtain sample-specific blank corrections. Lithium carbide synthesis is likely to prove a source of contamination. This work suggests that reproducible background levels for routine dating of less than 0.1 pMC (55 ka 14C yr) are achievable.

Type
Articles
Information
Radiocarbon , Volume 46 , Issue 1: Proceedings of the 18th International Radiocarbon Conference (Part 1 of 2), Conference Editors: Nancy Beavan Athfield, Rodger J Sparks , 2004 , pp. 123 - 131
Copyright
Copyright © 2004 by the Arizona Board of Regents on behalf of the University of Arizona 

References

Bevington, PR. 1969. Data Reduction and Error Analysis for the Physical Sciences. New York: McGraw-Hill.Google Scholar
Bronk Ramsey, C, Higham, TFG, Leach, P. 2004. Towards high-precision AMS: progress and limitations. Radiocarbon , these proceedings.CrossRefGoogle Scholar
Hogg, AG, Lowe, DJ, Hendy, CH. 1987. University of Waikato radiocarbon dates I. Radiocarbon 29(2):263–301.CrossRefGoogle Scholar
Hogg, AG. 1993. Counting performance and design of 0.3-mL to 10-mL synthetic silica liquid scintillation vials for low-level 14C determination. In: Noakes, JE, Schönhofer, F, Polach, HA, editors. International Conference on Advances in Liquid Scintillation Spectrometry 1992. Tucson, Arizona: Radiocarbon. p 135–42.Google Scholar
Hoper, ST, McCormac, FG, Hogg, AG, Higham, TFG, Head, MJ. 1997. Evaluation of wood pretreatments on oak and cedar. Radiocarbon 40(1):45–50.Google Scholar
Long, A, Kalin, RM. 1992. High-sensitivity radiocarbon dating in the 50,000 to 70,000 BP range without isotopic enrichment. Radiocarbon 34(3):351–9.CrossRefGoogle Scholar
McCormac, FG, Kalin, RM, Long, A. 1993. Radiocarbon dating beyond 50,000 years by liquid scintillation counting. In: Noakes, JE, Schönhofer, F, Polach, HA, editors. International Conference on Advances in Liquid Scintillation Spectrometry 1992. Tucson, Arizona: Radiocarbon. p 125–33.Google Scholar
Newnham, RM, Alloway, BV. 2001. The last interglacial/glacial cycle in Taranaki, western North Island, New Zealand: a palynostratigraphic model. In: Goodman, DK, Clarke, RT, editors. Proceedings of the IX International Palynological Congress, Houston (1996). Dallas, Texas: American Association of Stratigraphic Palynologists Foundation. p 411–22.Google Scholar
Scott, EM, editor. 2003. The Third International Radiocarbon Intercomparison (TIRI) and the Fourth International Radiocarbon Intercomparison (FIRI), 1990–2002. Radiocarbon 45(2):135–408.Google Scholar