Department of Physics, Kyungpook National University
경북대학교 물리학과
The possibility of manipulating the nuclear spins constitutes an important asset for any nuclear physics experiment. The control over this additional degree of freedom could provide more profound nuclear structure information, not accessible by other means. For example a spin-polarized ensemble can be used for determining the ground-state nuclear moments of beta-decaying nuclei. Nuclear reactions with spin-polarized nuclei could be used for a direct determination of nuclear spins of excited states as usually done in e.g. transfer or Coulomb-excitation reactions. An ensemble of spin-polarized microsecond isomeric states is a unique tool allowing the determination the sign of the quadrupole moment of the state of interest.
Nuclear spin polarization can be obtained in projectile fragmentation reactions. Few examples of the use of polarized beams at several different laboratories, e.g. RIKEN, GANIL and NSCL, will be presented. Another point that will be emphasized is the polarization of low-energy ISOL radioactive beams. Some application of the Tilted Foils technique at TRIAC, Japan and at ISOLDE, CERN will be presented. The insight of those recent measurements to the polarization process will be discussed together with some ideas for post-acceleration of polarized radioactive beams.
Nuclear moments are an important ingredient of our knowledge and understanding of the nuclear structure far from the beta-stability line. The nuclear magnetic moments are very sensitive probe to the single particle structure of the nuclei. They can serve as a test of the purity of their nuclear wave functions and to the theoretical models. The quadrupole moments give direct informations on the collectivity and the shape of the nucleus.
The discovery of nuclear spin alignment in projectile fragmentation reactions has led to the opportunity to perform such measurements in the neutron-rich exotic region. A powerful method to study isomeric states is the well-known Time Dependent Angular Distribution (TDPAD) technique, usually applied to isomers produced by fusion evaporation. It was our aim to extend the applicability of this technique to fragmentation isomers. So far g-factor and quadrupole moment measurements of projectile fragmentation isomers have been successfully performed. Experimental improvements and results obtained by our collaboration will be presented. The near future perspectives will be discussed.
