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