A new technique for counting very rare isotopes using atom trapping laser techniques developed by nuclear physicists at Argonne National Laboratory has many applications in earth sciences. This technique uses a series of laser beams to trap atoms of a particular isotope. The trap can be tuned to accept only an atom of a particular isotope, allowing the device to count individual atoms of rare isotopes. The device can count these rare isotopes down to levels of one atom out of every ten trillion atoms of the more common isotope found in nature. The device has uses for dating ice and water for geological studies, or monitoring nuclear waste in the environment. 81
Kr analyses can be used to determine the ages of old ice and groundwater in a range (5×104
years) beyond the reach of radio-carbon dating; Analyses of 85
Kr, a fission product of uranium and plutonium, can serve as a means to help verify compliance with the Nuclear Non-Proliferation Treaty. For example, it can be used to detect 85
Kr, a noble gas released into the neighboring atmospheric environment during the process of recovering plutonium from nuclear fuels. By counting atoms instead of the traditional way of counting decays, ATTA-enabled instruments are immune to radioactive backgrounds and are capable of on-site analyses. Moreover, in the event of a nuclear fallout incident, such instruments can be used to measure the level of environmental contamination and biological absorption of radioactive isotopes.