Researchers at Argonne National Laboratory have demonstrated an ultrasensitive trace analysis technique based on magneto-optical trapping that can measure the isotopic ratio of atmospheric krypton gas. While in the trap, a krypton atom scatters tens of millions of photons per second from the laser beams and appears as a bright dot. An avalanche photodiode records the arrival and departure of individual atoms. Unlike these other forms of trace analysis, atom trap trace analysis does not require pure samples or isolation from environmental noise.
Potential applications abound for the atom trap trace technique.
In accelerator mass spectrometry, atoms from a sample are sent through a particle accelerator and stripped of their electrons, and a sensitive detector measures their mass. However, the large accelerator facilities required make this process expensive and impractical for many applications. Accelerator mass spectrometry, which uses a mass analyzer, suffers from isobar contamination caused by atoms or molecules that have the same mass number. According to Lu, his team's work could open up a range of applications, including monitoring bone-loss rates in the diagnosis and assessment of osteoporosis, and monitoring nuclear reactor safety and environmental contamination. In the near term, the researchers will continue to focus on improving the technique using krypton, but they could look to other tracers in the future.