Physics Colloquium

"Atom Trap Trace Analysis"

Presented by Prof. Zheng-Tian Lu, Argonne National Laboratory

Tuesday, November 8, 2011, 3:30 pm — Hamilton Seminar Room, Bldg. 555

Since the invention of radiocarbon dating in 1949, trace analyses of long-lived cosmogenic isotopes have contributed to a wide range of scientific and technological areas. We have developed an analytical method called Atom Trap Trace Analysis (ATTA), in which individual atoms of the desired isotope are selectively captured and detected with a laser-based atom trap. ATTA possesses a superior selectivity and is used to analyze environmental radio-isotopes: 81Kr, 85Kr, and 39Ar. These three isotopes have extremely low isotopic abundances in the range of 10^-16 - 10^-11, and cover a wide range of ages and applications. As the first real-world application of ATTA, we have determined the mean residence time of the old groundwater in the Nubian Aquifer located underneath the Sahara Desert. Moreover, this method of capturing and probing atoms of rare isotopes is also applied to experiments that study exotic nuclear structure and test fundamental symmetries. This work is supported by DOE, Office of Nuclear Physics, and by NSF, Division of Earth Sciences.

Hosted by: Aihong Tang

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