Magnetic moment and electric quadrupole moment of the 18N ground state

The magnetic moment and electric quadrupole moment of a neutron-rich nucleus N-18 have been determined by the beta-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 beta-NMR experiment. From the observed resonance in a Pt stopper the magnetic moment for the N-18 ground state has been determined to be \mu\ = 0.3279 +/- 0.0013 mu(N). The N-18 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 mu and Q are compared with shell model calculations. (C) 1999 Published by Elsevier Science B.V. All rights reserved.