³⁹Ar/Ar measurements using ultra-low background proportional counters.

Appl Radiat Isot

Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States.

Published: January 2016

Age-dating groundwater and seawater using the (39)Ar/Ar ratio is an important tool to understand water mass-flow rates and mean residence time. Low-background proportional counters developed at Pacific Northwest National Laboratory use mixtures of argon and methane as counting gas. We demonstrate sensitivity to (39)Ar by comparing geological (ancient) argon recovered from a carbon dioxide gas well and commercial argon. The demonstrated sensitivity to the (39)Ar/Ar ratio is sufficient to date water masses as old as 1000 years.

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http://dx.doi.org/10.1016/j.apradiso.2015.10.006DOI Listing

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