Bonn 2000 – wissenschaftliches Programm
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MS: Massenspektrometrie
MS IV: HV IV
MS IV.1: Hauptvortrag
Dienstag, 4. April 2000, 11:00–11:30, HS VII
A new method of ultra-trace analysis — •C.Y. Chen1, K. Bailey1, X. Du1, Y.M. Li1, Z.-T. Lu1, T.P. O’Connor1, and L. Young2 — 1Physics Division — 2Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
A new method of ultrasensitive isotope trace analysis has been developed. This method, based on the technique of laser manipulation of neutral atoms, has been used to count individual 85Kr and 81Kr atoms present in a natural Kr gas sample with isotopic abundance in the range of 10−11 and 10−13, respectively. In this setup we apply DC discharge to a sample of Kr gas to produce a metastable Kr (Kr*) atom beam. This thermal Kr* beam is then decelerated via the Zeeman slowing technique and loaded into a magneto-optical trap. In the trap the fluorescence from a single trapped atom is imaged onto an avalanche photodiode detector operated in the photon-counting mode. With this design the system is capable of trapping one 81Kr atom in 20 minutes with a total efficiency of 1× 10−7. Our near term goal is to improve the system efficiency, hopefully by a few orders of magnitude, by applying cryogenic cooling to the Kr atoms in the discharge region and by re-circulating the Kr gas. This work is supported by the U.S. Department of Energy under contract W-31-109-ENG-38.