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Events in Physics
Title: Atom Trap, Krypton-81, and Saharan Water    (Colloquia)
Start Date: 02/07/2005
Time: 4:30 pm
Location: 1 LeConte Hall
Speaker: Dr. Zheng-Tian Lu
Affiliation: Physicist, Physics Division, ANL
Contact Person: K. Lee   (510) 642-3034
Details: Since radiocarbon dating was first demonstrated in 1949, the field of trace analyses of long-lived cosmogenic isotopes has seen steady growth in both analytical methods and applicable isotopes. The impact of such analyses has reached a wide range of scientific and technological areas. A new method, named Atom Trap Trace Analysis (ATTA), was developed by our group and used to analyze 81Kr in environmental samples. In this method, individual 81Kr atoms are selectively captured and detected with a laser-based atom trap. 81Kr is produced by cosmic rays in the upper atmosphere. It is the ideal tracer for dating ice and groundwater. 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.

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