Heidelberg 2015 – scientific programme

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UP: Fachverband Umweltphysik

UP 6: PV Lu

UP 6.1: Plenary Talk

Thursday, March 26, 2015, 09:45–10:30, PV-Rooms

Atom Trap, Krypton-81, and Global Groundwater — •Zheng-Tian Lu — Argonne National Laboratory, Lemont, USA — The University of Chicago, Chicago, USA

The long-lived noble-gas isotope ⁸¹Kr is the ideal tracer for water and ice with ages of 10⁵ - 10⁶ years, a range beyond the reach of ¹⁴C. ⁸¹Kr-dating, a concept pursued over the past five decades by numerous laboratories employing a variety of techniques, is finally available to the earth science community at large. This is made possible by the development of the Atom Trap Trace Analysis (ATTA) method, in which individual atoms of the desired isotope are captured and detected. ATTA possesses superior selectivity, and is thus far used to analyze the environmental radioactive isotopes ⁸¹Kr, ⁸⁵Kr, and ³⁹Ar. These three isotopes have extremely low isotopic abundances in the range of 10⁻¹⁶ to 10⁻¹¹, and cover a wide range of ages and applications. In collaboration with earth scientists, we are dating groundwater and mapping its flow in major aquifers around the world. We have also demonstrated for the first time ⁸¹Kr-dating of old ice.

This work is supported by U.S. DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.