MAGNETIC MOMENT AND ELECTRIC QUADRUPOLE MOMENT OF THE 18N GROUND STATE

Abstract The magnetic moment and electric quadrupole moment of a neutron-rich nucleus 18 N have been determined by the β -NMR method, taking advantage of the fragment spin polarization induced in the intermediate-energy projectile fragmentation reaction. To assure the existence of a sufficient polarization prior to the resonance search, a scheme of polarization measurement by means of an adiabatic field rotation has been developed and successfully incorporated in the β -NMR experiment. From the observed resonance in a Pt stopper the magnetic moment for the 18 N ground state has been determined to be | μ |=0.3279±0.0013 μ N . The 18 N fragments have also been implanted in a single crystal Mg stopper, and from the observed quadrupole frequency | eqQ / h |=73.2±1.4 kHz, the electric quadrupole moment | Q |=12.3±1.2 mb has been deduced. The obtained μ and Q are compared with shell model calculations.