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Effect of Beam Transmission of Stable Isotopes on Online δ13C for SSAMS

Published online by Cambridge University Press:  23 July 2019

G V Ravi Prasad*
Affiliation:
Center for Applied Isotope Studies, University of Georgia, 120 Riverbend Rd., Athens, GA 30602, USA
Alexander Cherkinsky
Affiliation:
Center for Applied Isotope Studies, University of Georgia, 120 Riverbend Rd., Athens, GA 30602, USA
Randy Culp
Affiliation:
Center for Applied Isotope Studies, University of Georgia, 120 Riverbend Rd., Athens, GA 30602, USA
*
*Corresponding author. Email: [email protected].

Abstract

It is known that 12C beam transmission through the accelerator decreases at high beam currents. This effect depends on machine design and varies across different types of AMS instruments. For beam currents of about 100 μA, the effect is small on the 500 kV tandem CAMS unit, whereas beam saturation is observed for similar high beam currents on the 250 kV SSAMS unit. While this effect is very evident for high 12C beam currents, we have also observed that even the 13C beam is found to suffer modest transmission loss with beam current. As a result, the 13C/12C ratio does not remain constant with beam current. By correcting for the effects of 12C beam saturation and decreased 13C transmission, we have obtained online δ13C values that are more accurate and precise at moderately high beam currents for SSAMS.

Type
Conference Paper
Copyright
© 2019 by the Arizona Board of Regents on behalf of the University of Arizona 

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Footnotes

Selected Papers from the 23rd International Radiocarbon Conference, Trondheim, Norway, 17–22 June, 2018

References

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