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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-2244
DTSTART:20120127T213000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T071614Z
LAST-MODIFIED:20120117T140847Z
LOCATION:2241 Chamberlin Hall (coffee at 4:30 pm)
SUMMARY:Atom Trap\, Krypton-81\, and Global Groundwater\, Physics Depa
 rtment Colloquium\, Zheng-Tian Lu\, Argonne National Laboratory & the 
 University of Chicago
DESCRIPTION:The long-lived noble-gas isotope <sup>81</sup>Kr is the id
 eal tracer for old water and ice in the age range of 10^5 - 10^6 years
 \, a range beyond the reach of <sup>14</sup>C. <sup>81</sup>Kr-dating\
 , a concept pursued over the past four decades by numerous laboratorie
 s employing a variety of techniques\, is now available for the first t
 ime to the earth science community at large. This is made possible by 
 the development of an atom counter based on the Atom Trap Trace Analys
 is (ATTA) method\, in which individual atoms of the desired isotope ar
 e 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 <sup>81</sup>Kr\, <sup>85</sup>Kr\,
  and <sup>39</sup>Ar\, These three isotopes have extremely low isotopi
 c abundances in the range of 10^-16 to 10^-11\, and cover a wide range
  of ages and applications. In collaboration with earth scientists\, we
  are dating groundwater and mapping its flow in major aquifers around 
 the world.
URL:https://www.physics.wisc.edu/events/?id=2244
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