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A Gas Ion Source for Radiocarbon Measurements at 200 kV

Published online by Cambridge University Press:  18 July 2016

M Ruff
Affiliation:
Department of Chemistry and Biochemistry, University of Bern, Switzerland Paul Scherrer Institute, Villigen, Switzerland
L Wacker*
Affiliation:
Institute for Particle Physics, ETH Zurich, Switzerland
H W Gäggeler
Affiliation:
Department of Chemistry and Biochemistry, University of Bern, Switzerland Paul Scherrer Institute, Villigen, Switzerland
M Suter
Affiliation:
Institute for Particle Physics, ETH Zurich, Switzerland
H-A Synal
Affiliation:
Paul Scherrer Institute, c/o ETH Zurich, Switzerland
S Szidat
Affiliation:
Department of Chemistry and Biochemistry, University of Bern, Switzerland Paul Scherrer Institute, Villigen, Switzerland
*
Corresponding author. Email: wacker@phys.ethz.ch
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Abstract

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The novel tabletop miniaturized radiocarbon dating system (MICADAS) at ETH Zurich features a hybrid Cs sputter negative ion source for the measurement of solid graphite and gaseous CO2 samples. The source produces stable currents of up to 6 μA C out of gaseous samples with an efficiency of 3–6%. A gas feeding system has been set up that enables constant dosing of CO2 into the Cs sputter ion source and ensures stable measuring conditions. The system is based on a syringe in which CO2 gas is mixed with He and then pressed continuously into the ion source at a constant flow rate. Minimized volumes allow feeding samples of 3–30 μg carbon quantitatively into the ion source. In order to test the performance of the system, several standards and blanks have successfully been measured. The ratios of 14C/12C could be repeated within statistical errors to better than 1.0% and the 13C/12C ratios to better than 0.2%. The blank was <1 pMC.

Type
Articles
Copyright
Copyright © 2007 by the Arizona Board of Regents on behalf of the University of Arizona 

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