Hostname: page-component-848d4c4894-4hhp2 Total loading time: 0 Render date: 2024-05-05T15:51:51.043Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Rights & Permissions [Opens in a new window]

Extract

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.

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

Andrée, M, Beer, J, Oeschger, H, Bonani, G, Hofmann, H J, Morenzoni, E, Nessi, M, Suter, M and Wölfli, W, 1984, Target preparation for milligram-sized 14C samples and data evaluation for AMS measurements: Nuclear Instruments & Methods, v 223, no. B5, p 274–279.CrossRefGoogle Scholar
Beukens, R P and Lee, H W, 1981, The production of small carbon samples by R F dissociation of acetylene, in Kutschera, W, ed, Symposium on Accelerator Mass Spectrometry, 2nd, Proc: Argonne Natl Lab, p 416–425.Google Scholar
Boudouard, O, 1902, Recherches sur les équilibres chimiques: Ann Chim Phys, v 24, ser 7, p 5–85.Google Scholar
Jull, A J T, Donahue, D J, Hatheway, A L, Linick, T W and Toolin, L J, 1986, Production of graphite targets by deposition from CO/H2 for precision accelerator 14C measurements, in Stuiver, M and Kra, R S, eds, Internatl 14C conf, 12th, Proc: Radiocarbon, v 28, no 2A, p 191–197.Google Scholar
Lowe, D C, 1984, Preparation of graphite targets for radiocarbon dating by tandem accelerator mass spectrometry: Internatl Jour Applied Radiation Isotopes, v 35, p 349–352.CrossRefGoogle Scholar
Schenck, R and Zimmerman, F, 1903, Ueber die Spaltung des Kohlenoxyds und das Hochofengleichgewicht: Berichte deutschen chem Gesellschaft, v 36, p 1231–1235.CrossRefGoogle Scholar
Slota, P J Jr and Taylor, R E, 1986, AMS 14G analysis of samples from archaeological contexts: pretreatment and target preparation, in University of California AMS conf Proc: Livermore, Inst Geophysics Planetary Physics.Google Scholar
Vogel, J S, Southen, J R, Nelson, D E and Brown, T A, 1984, Performance of catalytically condensed carbon for use in accelerator mass spectrometry: Nuclear Instruments & Methods, v 223, no. B5, p 289–293.CrossRefGoogle Scholar
Wagman, D D, Kilpatrick, J E, Taylor, W J, Pitzer, K S and Rossini, F D, 1945, Heats, free energies and equilibrium constants of some reactions involving D2, H2, H2O, C, CO, CO2 and CH4 : Jour Research Natl Bur Standards, v 34, p 143–161.Google Scholar
Wand, J O, Gillespie, R and Hedges, R E M, 1984, Sample preparation for accelerator-based radiocarbon dating: Jour Archaeol Sci, v 11, p 159–163.CrossRefGoogle Scholar