INTERACTION CROSS-SECTIONS AND RADII OF THE MASS-NUMBER A=17 ISOBAR (N-17, 17F, AND NE-17)

Interaction cross sections of mass number A = 17 isobar (N-17(7)10, F- 17(9)8, and Ne-17(10)7) have been measured at around 700 MeV/nucleon. Effective root-mean-square (RMS) radii of the nucleon distribution of these nuclei have been deduced using Glauber-model calculation. A stro ng isospin dependence of the radii has been observed in the A = 17 iso bar, which shows an increase of the radii on the proton rich side from F-17 to Ne-17. The radius of Ne-17 is also found to be larger than th at of its mirror nucleus N-17. The increase of the radius in Ne-17 sug gests its anomalous structure. One of the possibilities is that an inv ersion of the s and d orbitals occurs in this nucleus. The role of the centrifugal barrier in the formation of a halo is also discussed.