Atom Trap Trace Analysis at ANL

Application/instrumentation:

Atom Trap Trace Analysis (ATTA) to determine isotopic abundances.

Developed at:

Argonne National Laboratory

Developed in:

1999-current

Result of NP research:

Precision measurements of isotopes

Application currently being supported by:

DOE-NP, NSF-Earth Science

Impact/benefit to spin-off field:

Used to date old ground water, non-proliferation monitoring, Radio-Krypton Dating

A new technique for counting very rare isotopes using atom trapping laser techniques developed by nuclear physicists at Argonne National Laboratory has many applications in earth sciences. This technique uses a series of laser beams to trap atoms of a particular isotope. The trap can be tuned to accept only an atom of a particular isotope, allowing the device to count individual atoms of rare isotopes. The device can count these rare isotopes down to levels of one atom out of every ten trillion atoms of the more common isotope found in nature. The device has uses for dating ice and water for geological studies, or monitoring nuclear waste in the environment.

⁸¹Kr analyses can be used to determine the ages of old ice and groundwater in a range (5×10⁴ - 1×10⁶ years) beyond the reach of radio-carbon dating; Analyses of ⁸⁵Kr, a fission product of uranium and plutonium, can serve as a means to help verify compliance with the Nuclear Non-Proliferation Treaty. For example, it can be used to detect ⁸⁵Kr, a noble gas released into the neighboring atmospheric environment during the process of recovering plutonium from nuclear fuels. By counting atoms instead of the traditional way of counting decays, ATTA-enabled instruments are immune to radioactive backgrounds and are capable of on-site analyses. Moreover, in the event of a nuclear fallout incident, such instruments can be used to measure the level of environmental contamination and biological absorption of radioactive isotopes.

Researchers at Argonne National Laboratory have determined the ages of groundwater at six sites, ranging from 200,000 to 1,000,000 years, in the Nubian Aquifer underneath the Eastern Sahara Desert. These results revealed hydrologic behavior of this huge aquifer, with important implications for climate history and water resource management in the region. With this demonstration, widespread application of ⁸¹Kr in Earth sciences now appears feasible.