Magnetic moments of ³⁰₁₃Al₁₇ and ³²₁₃Al₁₉

Abstract

Ground-state magnetic moments of ³⁰Al and ³²Al were measured with the β-NMR method using radioactive-isotope beams spin-polarized in the projectile-fragmentation reaction. Polarization of sizes $|P|=0.5\text{–}1\%$ were obtained in spite of the large numbers of nucleons that are removed from the projectile ⁴⁰Ar, providing a promising prospect that substantial polarizations are obtained even in fragment nuclei that are far removed from the projectile nucleus. The obtained μ moments, $|{\mu }_{\exp }({}^{30}\mathrm{Al})|=3.010(7){\mu }_{\mathrm{N}}$ and $|{\mu }_{\exp }({}^{32}\mathrm{Al})|=1.959(9){\mu }_{\mathrm{N}}$, are in agreement with shell model calculations within the sd valence space, although a reduction in the energy-gap between the sd and pf states is predicted for ³²Al in recent theoretical studies.