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<div align="center"><font face="Times New Roman" size="6" color="navy"><b>Old Dominion University</b></font></div>
<div align="center"><font face="Times New Roman" size="6" color="navy"><b>Department of Physics</b></font></div>
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<div align="center"><font face="Times New Roman" size="6" color="#31849B"><b>Fall Colloquium Series</b></font></div>
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<div align="center"><font face="Times New Roman" size="5" color="#17365D"><b>Tuesday September 4, 2012</b></font></div>
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<div align="center"><font face="Times New Roman" size="5" color="#31849B"><b>"Atom Trap, Krypton-81, and Global Groundwater"</b></font></div>
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<font face="Times New Roman" color="#1F497D"><b>Dr. Zheng-Tian Lu<br>
Argonne National Laboratory</b></font></font></div>
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<div align="left"><font size="3"> <font face="Times New Roman" size="4">The long-lived noble-gas isotope </font><font face="Times New Roman" size="2"><sup>81</sup></font><font face="Times New Roman" size="4">Kr
is the ideal tracer for old water and ice in the age range of 10^5 - 10^6 years, a range beyond the reach of </font><font face="Times New Roman" size="2"><sup>14</sup></font><font face="Times New Roman" size="4">C.
</font><font face="Times New Roman" size="2"><sup>81</sup></font><font face="Times New Roman" size="4">Kr-dating, a concept pursued over the past four decades by numerous laboratories
employing a variety of techniques, is now available for the first time to the geoscience community at large.</font><font face="Times New Roman" size="4"> This is made possible by the development of an atom counter based
on the Atom Trap Trace Analysis (ATTA) method, </font><font face="Times New Roman" size="4">in which individual atoms of the desired isotope are selectively captured and detected with a laser-based atom trap. ATTA possesses
superior selectivity, and is thus far used to analyze the environmental radioactive isotopes </font><font face="Times New Roman" size="2"><sup>81</sup></font><font face="Times New Roman" size="4">Kr,
</font><font face="Times New Roman" size="2"><sup>85</sup></font><font face="Times New Roman" size="4">Kr, and </font><font face="Times New Roman" size="2"><sup>39</sup></font><font face="Times New Roman" size="4">Ar,
These three isotopes have extremely low isotopic abundances in the range of 10^-16 to 10^-11, and cover a wide range of ages and applications. In collaboration with geoscientists, we are dating groundwater and mapping its flow in major aquifers around the
world.</font></font></div>
<div align="left"><font face="Times New Roman" size="4">This work is supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357; and by NSF, Division of Earth Sciences,
under award EAR-0651161<font size="3">.</font></font></div>
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<div align="center"><font face="Times New Roman" size="5">Presentation: OCNPS 200 @ 3:00 pm</font></div>
<div align="center"><font face="Times New Roman" size="5">Refreshments: Atrium @ 2:30 pm </font></div>
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<div align="center"><font face="Times New Roman" size="5">More details at <a href="http://sci.odu.edu/physics/"><font color="blue"><u>http://sci.odu.edu/physics/</u></font></a></font></div>
<div align="center"><font face="Times New Roman" size="5">All are Welcome!</font></div>
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