Browsing Radiocarbon, Volume 28 (1986) by Subjects
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Production of Graphite Targets by Deposition from Co/H2 for Precision Accelerator 14C MeasurementsA method has been developed at the Arizona AMS facility for production of graphite directly from CO2 by catalytic reduction of CO/H2 mixtures. The method is a modification of procedures discussed by Vogel et al (1984). Currents of 12C- from these targets vary considerably, but have a median value which is 70% of that achieved from spectroscopic graphite. Precisions of +/- 60 to 100 yr are routinely achieved for 14C ages of 5000-yr-old samples containing one milligram of carbon. The yield of 14C from "blank" targets is 0.6 +/- 0.1% of that from modern material.