Trapping and detecting single atoms for ancient Egyptian groundwater dating, and biomedical sample analyses
Iain Moore (Argonne National Lab)

Ultrasensitive isotope trace analysis is an established and valuable tool with a wide range of applications in both commercial and scientific fields. The existing methods have now been complemented by Atom Trap Trace Analysis (ATTA), an atom-trap based method recently developed by our group at the Argonne National Laboratory.

81Kr (t_1/2 = 2.3 × 10^5 a, 81Kr/Kr ~ 10^-13) is the ideal tracer isotope for dating old groundwater and ice in the range of 10^5 – 10^6 years. An expedition to Egypt in 2002 collected groundwater samples for the dating of the Nubian Aquifer, one of the world’s largest groundwater reservoirs. The analysis of 41Ca (t_1/2 = 1.03 × 10^5 a, 41Ca/Ca ~ 10^-14 in modern bones) aims to provide a new tool for archeological and geological dating in an age range that is difficult to date with existing methods. ATTA recently reached a first milestone with the detection of single atoms of 41Ca in biomedical samples at the pre-enriched abundance level of 10^-8 – 10^-10 (with respect to 40Ca).