Probing Structure at the femto meter scale
Prof. Hans A. Schuessler (Texas A&M University, U.S.A.)

I report on our work to measure radii, deformations, and nuclear moments of nuclei far off stability. These measurements yield information on the nuclear force and thus test global nuclear models. The research is based on laser- and rf-spectroscopy on-line to nuclear accelerators at several laboratories all over the world. Both collinear fast ion beam and ion storage techniques are being used. For the collinear fast beam, we achieved a selectivity of one part in 10^10 and a sensitivity of 10^3 ions/s. In ion storage, ions produced with several 100 MeV energy in a nuclear reaction were decelerated, then laser cooled to a few meV and stored in an ion trap.
Two new devices namely the combined linear ion trap and the rf-ion funnel were developed for this purpose. In a recent precision measurement single ion spectroscopy has been demonstrated, and resulted in the observation of the distribution of the nuclear magnetism in 9Be. We obtained accuracies of 10^-9 for the nuclear spin flip transitions, and 10^-7 for the electron spin flip transitions. Future extensions of this research to the halo nucleus 11Be will be indicated.