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Preparation of Small Samples for 14C Accelerator Targets by Catalytic Reduction of CO

Published online by Cambridge University Press:  18 July 2016

P J Slota Jr ,
A J T Jull ,
T W Linick  and
L J Toolin
P J Slota Jr
Affiliation:
Radiocarbon Laboratory, Department of Anthropology, University of California, Riverside, California 92521
A J T Jull
Affiliation:
Radiocarbon Laboratory, Department of Anthropology, University of California, Riverside, California 92521
T W Linick
Affiliation:
Radiocarbon Laboratory, Department of Anthropology, University of California, Riverside, California 92521
L J Toolin
Affiliation:
Radiocarbon Laboratory, Department of Anthropology, University of California, Riverside, California 92521
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Graphite in various forms has become the standard target for accelerator 14C dating. Graphite has been made by catalytic graphitization of charcoals (Lowe, 1984). Thin films of graphite have also been produced by thermal cracking (Beukens & Lee, 1981), electric discharge (Andrée et al, 1984; Wand, Gillespie & Hedges, 1984). Vogel et al (1984) pointed out the ease of graphite formation on iron from CO2 and H2 mixtures at ca 600°C. The deposition reactions of carbon from the CO, H2, and CO2 equilibria are well known (Wagman et al, 1945) and well studied. Formation of graphite from CO2 was discussed extensively by Boudouard (1902) and Schenck and Zimmerman (1903), and was known to chemists in France in 1851. We have used a related method, where graphite forms away from the iron, by using a higher temperature, and reduction of CO2 to CO over Zn in the presence of H2 (Jull et al, 1986) as an alternative to the use of Fe alone. The object of this paper is to point out an even simpler graphite preparation system, which eliminates hydrogen. The decomposition reaction of CO (Boudouard, 1902) takes place according to reaction (1).

Type
Notes and Comments
Information
Radiocarbon , Volume 29 , Issue 2 , 1987 , pp. 303 - 306
Copyright
Copyright © The American Journal of Science 

References

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