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Physical Society ColloquiumAtom Trap, Krypton-81 and Saharan WaterZ.T. LuArgonne National LaboratorySince 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 analyse 81Kr in environmental samples. In this method, individual 81Kr atoms are selectively captured and detected with a laser-based atom trap. 81Kr is produced in the upper atmosphere by cosmic-ray induced spillation and neutron activation of stable krypton isotopes. It is the ideal tracer for dating ice and groundwater in the age range of 104-106 years. 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.
Friday, November 19th 2004, 15:30
Ernest Rutherford Physics Building, Key Auditorium (room 112) |