Argonne National Laboratory

Radiokrypton Dating Center

Radiokrypton Dating Center

Argonne's Radiokrypton Dating Facility has advanced the science of krypton dating to a practical level for young (10 – 50 years) and ancient (30 – 2000 kyrs) groundwater and glacial ice with Atom Trap Trace Analysis (ATTA).

Since our first demonstration of Krypton-81 dating in 1999, which employs a laser-based atom trap to selectively capture and detect the isotope of interest, we have improved the sensitivity of our technique by orders of magnitude – now allowing rapid dating of small (< 10 microliters of krypton gas at standard temperature and pressure) samples.

ATTA can measure the relative isotopic abundance of Krypton-81 and Krypton-85 in environmental samples of ice, water and air. ATTA is extremely sensitive and selective, allowing us to detect isotopes whose isotopic abundance is less than one part in 1015.

The half-lives of 81Kr (~230,000 years) and 85Kr (~10 years) allow for dating over a wide range of ages and can ideally complement the dating range of other isotopes such as 14C (~5,700 yrs).

Our third-generation atom-trapping apparatus was specifically designed for routine radiokrypton analysis and is ready for operation. In addition, we are currently building an additional state-of-the-art ATTA instrument as part of our Radiokrypton Dating Center for increased sample throughput and increased availability to accommodate demand.