Hannover 2003 – scientific programme
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MS: Massenspektrometrie
MS III: HV III
MS III.1: Invited Talk
Monday, March 24, 2003, 12:00–12:30, F 428
The AlCaTraz experiment: Towards ultra-sensitive isotope analysis of calcium — •Ronnie Hoekstra, Steven Hoekstra, and Reinhard Morgenstern — KVI, Atomic Physics, RijksUniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen, the Netherlands
We are developing a new apparatus for ultra-sensitive trace isotope analysis of calcium isotopes. Using modern optical methods, specific isotopes of calcium will be selectively cooled, trapped and detected in a Magneto-Optical Trap (MOT). Of special interest is the radioactive isotope 41Ca, which might be used for dating calcium-containing material from the pleistocene (the half-life of 41Ca is 105,000 year) and as a biomedical tracer for the osteoporosis studies. The main experimental challenge is the very low natural abundance of 41Ca relative to 40Ca, which is only 10−15 to 10−14. Until now this kind of experiments have only been attempted with Accelerator Mass Spectrometry and more recently Resonant Ionization Mass Spectrometry. In our AlCaTraz experiment, Ca is evaporated from an oven, after which the atoms are decelerated in a Zeeman slower. Before and after the Zeeman slower, optical molasses is used to collimate the atom beam, and after the Zeeman slower also to deflect the desired isotope. These atoms are then captured in a standard MOT, and detected by their fluorescence. We performed Monte Carlo type simulations of the different stages, collimation, slowing down, deflection and trapping. In addition to the simulations, the experimental status will be discussed and as far as possible comparison will be made with the simulations.