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Production of Graphite Targets by Deposition from CO/H2 for Precision Accelerator 14C Measurements

Published online by Cambridge University Press:  18 July 2016

A J T Jull
Affiliation:
NSF Accelerator Facility for Radioisotope Analysis University of Arizona, Tucson, Arizona 85721
D J Donahue
Affiliation:
NSF Accelerator Facility for Radioisotope Analysis University of Arizona, Tucson, Arizona 85721
A L Hatheway
Affiliation:
NSF Accelerator Facility for Radioisotope Analysis University of Arizona, Tucson, Arizona 85721
T W Linick
Affiliation:
NSF Accelerator Facility for Radioisotope Analysis University of Arizona, Tucson, Arizona 85721
L J Toolin
Affiliation:
NSF Accelerator Facility for Radioisotope Analysis University of Arizona, Tucson, Arizona 85721
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Abstract

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A 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.

Type
I. AMS Techniques
Copyright
Copyright © The American Journal of Science 

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