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A Multiple Proportional 14C Counter System for Milligram-Sized Samples

Published online by Cambridge University Press:  18 July 2016

Gert Hut
Affiliation:
Isotope Physics Laboratory, University of Groningen The Netherlands
Jan Keyser
Affiliation:
Isotope Physics Laboratory, University of Groningen The Netherlands
Stef Wijma
Affiliation:
Isotope Physics Laboratory, University of Groningen The Netherlands
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Abstract

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A system of 10 proportional 14C counters has been designed. The counters have a volume of 35ml and are operated with CO2 at a pressure of 1 bar and a voltage of 3300V. The amplified signals of the counters are fed through an analog multiplexer to the inputs of three discriminators. The Geiger signal is fed to a separate discriminator. A logic circuit selects from these discriminators the alpha, beta, muon, and purity counts which are then stored in a microcomputer (ITT 2020 with 48K RAM), where the necessary calculations are also performed. The purity of the gas sample is monitored by counting a part of the muon spectrum. The alpha and beta pulses are stored during 95% of the measuring period; the remaining 5% is used for registration of the muon and purity pulses. The overall accuracy of the system for modern carbon samples is 2% after a counting period of 6 days.

Type
V. General Aspects of 14C Technique
Copyright
Copyright © The American Journal of Science 

References

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