Nuclear moment measurements of Neutron-rich Aluminum Isotopes Using Spin-polarized RI beams: Determination of the Boundary of the “Island of Inversion”

Abstract

The electric quadrupole moment Q for the ground state of 32Al has been measured using the β‐NMR technique. Spin‐polarized 32Al nuclei were obtained from the fragmentation of 40Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal α‐Al2O3 stopper. The quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value, |Q(32Alg.s.)| = 24(2) mb, was well reproduced by shell model calculations within the sd shell, indicating that 32Al is a normal sd‐shell nucleus. The result is in sharp contrast to the strongly deformed nuclei 32Mg and 31Mg neighboring the 32Al isotope.