Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-30T16:17:09.806Z Has data issue: false hasContentIssue false
  • English
  • Français

Liquid Scintillation Counter Characterization, Optimization and Benzene Purity Correction

Published online by Cambridge University Press:  18 July 2016

F. G. McCormac
F. G. McCormac*
Affiliation:
The Queen's University of Belfast, School of Geosciences, Palaeoecology Centre Belfast BT7 1NN, Northern Ireland
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.

In liquid scintillation counting (LSC), small variations in benzene purity can cause 14C pulse-height spectra to move with respect to the counting window. Thus, one must carefully monitor the purity of each benzene sample and apply corrections for spectral shifts. I describe here the techniques used at Queen's University Belfast for deriving correction factors for observed small variations in benzene purity. I also describe the methods used at our laboratory to fine-tune our Quantulus LS counters for high-precision dating. The tuning of the instruments minimizes the effect of fluctuations in gain that may occur during the long counting periods required for high-precision dating. Any remaining influences on efficiency owing to gain changes are corrected for, along with the purity correction, by continuous monitoring of the spectrum produced by the external source.

Type
Articles
Information
Radiocarbon , Volume 34 , Issue 1 , 1992 , pp. 37 - 45
Copyright
Copyright © The American Journal of Science 

References

Barker, H. 1953 Radiocarbon dating: Large scale preparation of acetylene from organic material. Nature 172: 631–632.CrossRefGoogle Scholar
Birks, J. B. 1970 Physics of the liquid scintillation process. In Bransome, E. D., ed., The Current Status of Liquid Scintillation Counting. New York, Grune and Shatton.Google Scholar
Coleman, D. D., Liu, C. L., Dickerson, D. R. and Frost, R. R. 1973 Improvement in trimerisation of acetylene to benzene for radiocarbon dating with a commercially available vanadium oxide catalyst. In Rafter, T. A. and Grant-Taylor, T., eds., Proceedings of the 8th International 14C Conference. Wellington, Royal Society of New Zealand 1: 158–170.Google Scholar
Noakes, J. E., Kim, S. M. and Stipp, J. J. 1965 Chemical and counting advances in liquid scintillation age dating. In Olsson, E. A. and Chatters, R. M., eds., Proceedings of the 6th International Conference on Radiocarbon and Tritium Dating. Clearinghouse for Federal Scientific and Technical Information, Washington, DC: 68–92.Google Scholar
Polach, H., Gower, J. and Fraser, I., 1973 Synthesis of high purity benzene for radiocarbon dating. In Rafter, T. A. and Grant-Taylor, T., eds., Proceedings of the 8th International 14C Conference. Wellington, Royal Society of New Zealand, 1: B36–B49.Google Scholar
Pearson, G. W. 1979 Precise 14C measurement by liquid scintillation counting. Radiocarbon 21(1): 1–21.CrossRefGoogle Scholar
Pearson, G. W. 1983 The development of high precision 14C measurement and its application to archaeological time-scale problems. Ph.D. thesis, The Queen's University Belfast.Google Scholar
Switsur, R. and Waterhouse, J. S. 1989 Benzene purity in radiocarbon dating samples. In Long, A. and Kra, R. S., eds., Proceedings of the 13th International 14C Conference. Radiocarbon 31(3): 260–263.CrossRefGoogle Scholar
Tamers, M. A. 1975 Chemical yield optimisation of the benzene synthesis for radiocarbon dating. International Journal of Applied Radiation Isotopes 26: 676–682.CrossRefGoogle Scholar
Witkin, D., Rigali, M. J., Kalin, R. M., Nagy, B. and Long, A. 1991 Impurities arising during benzene synthesis from acetylene on vanadium and chromium catalysts. Radiocarbon 33(2): 261–262. Abstract.Google Scholar