Hostname: page-component-848d4c4894-x24gv Total loading time: 0 Render date: 2024-06-09T07:34:37.839Z Has data issue: false hasContentIssue false
  • English
  • Français

Microscale AMS 14C Measurement at NOSAMS

Published online by Cambridge University Press:  18 July 2016

Ann Pearson ,
Ann P. Mcnichol ,
Robert J. Schneider ,
Karl F. Von Reden  and
Yan Zheng
Ann Pearson
Affiliation:
National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 USA
Ann P. Mcnichol
Affiliation:
National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 USA
Robert J. Schneider
Affiliation:
National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 USA
Karl F. Von Reden
Affiliation:
National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 USA
Yan Zheng
Affiliation:
Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 USA
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.

Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605°. Measured 14C/12C ratios of the resulting targets are affected by machine-induced isotopic fractionation, which appears directly related to the decrease in ion current generated by the smaller sample sizes. It is possible to compensate effectively for this fractionation by measuring samples relative to small standards of identical size. Examination of the various potential sources of background 14C contamination indicates that the sample combustion process is the largest contributor, adding ca. 1 μg of carbon with a less-than-modern 14C concentration.

Type
Part 1: Methods
Information
Radiocarbon , Volume 40 , Issue 1: 16th International Radiocarbon Conference 16-20,1997 Groningen , 1997 , pp. 61 - 75
Copyright
Copyright © The American Journal of Science 

References

Box, G. E. P., Hunter, W. G. and Hunter, J. S. 1978 Statistics for Experimenters: An Introduction to Design, Data Analysis, and Model Building. New York, J. Wiley and Sons: 653 p.Google Scholar
Brown, T. A. and Southon, J. R. 1997 Corrections for contamination background in AMS 14C measurements. In Jull, A. J. T., Beck, J. W., and Burr, G. S., eds., Proceedings of the 7th International Symposium on Accelerator Mass Spectrometry. Nuclear Instruments and Methods in Physics Research B123: 97–101.Google Scholar
Currie, L. A. and Polach, H. A. 1980 Exploratory analysis of the international radiocarbon cross-calibration data: Consensus values and interlaboratory error. In Stuiver, M. and Kra, R. S., eds., Proceedings of the 10th International 14C Conference. Radiocarbon 22(3): 933–935.CrossRefGoogle Scholar
Klinedinst, D. B., McNichol, A. P., Currie, L. A., Schneider, R. J., Klouda, G. A., von Reden, K. F., Verkouteren, R. M. and Jones, G. A. 1994 Comparative study of Fe-C bead and graphite target performance with the National Ocean Science AMS (NOSAMS) facility recombinator ion source. Nuclear Instruments and Methods in Physics Research B92: 166–171.Google Scholar
McNichol, A. P., Gagnon, A. R., Jones, G. A. and Osborne, E. A. 1992 Illumination of a black box: Analysis of gas composition during graphite target preparation. In Long, A. and Kra, R. S., eds., Proceedings of the 14th International 14C Conference. Radiocarbon 34(3): 321–329.Google Scholar
Rozanski, K., Stichler, W., Gonfiantini, R., Scott, E. M., Beukens, R. P., Kromer, B. and van der Plicht, J. 1992 The IAEA 14C intercomparison exercise 1990. In Long, A. and Kra, R. S., eds., Proceedings of the 14th International 14C Conference. Radiocarbon 34(3): 506–519 Google Scholar
Seguin, F. H., Schneider, R. J., Jones, G. A. and von Reden, K. F. 1994 Optimized data analysis for AMS radiocarbon dating. Nuclear Instruments and Methods in Physics Research B92: 176–181.Google Scholar
Stuiver, M. 1983 International agreements and the use of the new oxalic acid standard. In Stuiver, M. and Kra, R. S., eds., Proceedings of the 11th International 14C Conference. Radiocarbon 25(2): 793–795.Google Scholar
van der Borg, K., Alderliesten, C., de Jong, A. F. M., van den Brink, A., de Haas, A. P., Kersemaekers, H. J. H. and Raaymakers, J. E. M. J. 1997 Precision and mass fractionation in 14C analysis with AMS. In Jull, A. J. T., Beck, J. W., and Burr, G. S., eds., Proceedings of the 7th International Symposium on Accelerator Mass Spectrometry. Nuclear Instruments and Methods in Physics Research B123: 97–101.CrossRefGoogle Scholar
Verkouteren, R. M. and Klouda, G. A. 1992 Factorial design techniques applied to optimization of AMS graphite target preparation. In Long, A. and Kra, R. S., eds., Proceedings of the 14th International 14C Conference. Radiocarbon 34(3): 335–343.CrossRefGoogle Scholar
Vogel, J. S., Southon, J. R. and Nelson, D. E. 1987 Catalyst and binder effects in the use of filamentous graphite for AMS. In Gove, H. E., Litherland, A. E. and Elmore, D., eds., Proceedings of the 4th International Symposium on Accelerator Mass Spectrometry. Nuclear Instruments and Methods in Physics Research B29: 50–56.Google Scholar
Vogel, J. S., Nelson, D. E. and Southon, J. R. 1987 14C background levels in an accelerator mass spectrometry system. Radiocarbon 29(3): 323–333.Google Scholar
von Reden, K., McNichol, A., Pearson, A. and Schneider, R. 1998 14C AMS measurements of <100 μg samples with a high-current system. Radiocarbon, this issue.Google Scholar