Atom Trap Trace Analysis (ATTA) is an efficient and selective laser-based atom counting technique that provides radiokrypton (81Kr and 85Kr) dating to the earth science community. 81Kr (half-life = 230,000 yr) is an ideal tracer for old water and ice with mean residence times of 105-106 years, a range beyond the reach of 14C dating. 85Kr (half-life = 10.7 yr) is an increasingly important tracer for young groundwater in the age range of 5-50 years. Recent developments have improved the ATTA technique for both isotopes. For 81Kr, we have demonstrated measurements of 81Kr/Kr with relative uncertainties of 1% and placed an improved limit on anthropogenic 81Kr in the atmosphere, removing a systematic constraint to high precision 81Kr-dating. For 85Kr, we have developed new methodologies that increase sample throughput by over an order of magnitude to 6 samples in 24 hours. All the while, the ATTA-3 system at Argonne National Laboratory has continued to provide sample measurements to the scientific community and has now completed over 230 measurements in more than 25 collaborative projects which together span all seven continents.
Argonne Physics Division Seminar Schedule