We employ the Atom Trap Trace Analysis (ATTA) technique to measure ultralow 85Kr contamination in liquid Xe detectors, used by the XENON Collaboration to directly detect dark matter. ATTA has been demonstrated to be free of interferences from other isotopes, isobars, or molecular species even at the part-per-quadrillion (ppq) level. Beyond fundamental physics research, ultrasensitive radioisotope detection/dating can address key scientific questions in the earth sciences, with important consequences for e.g. water resource management and the study of climate change.

Photo by Ozier Muhammad/The New York Times.