Measurement of Electric Quadrupole Moments for 31Al Using Spin Polarized RI Beams

The electromagnetic moment is a sensitive probe to investigate microscopic structure. In order to measure the electromagnetic moment, β‐NMR and β‐NQR methods are employed taking advantage of the fragment spin polarization produced by the fragmentation reaction. The measurement of the electric quadrupole moment for ground‐state 31Al has been been carried out by β‐NQR method. Spin‐polarized 31Al nuclei were obtained from the fragmentation of 40Ar projectiles, and were implanted in α‐Al2O3 stopper. The electric quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value is |Q(31Al)| = 104(9) e⋅mb.