Angular-Correlation Study ofNa23Using theMg24(t,αγ)Na23Reaction

The ${\mathrm{Mg}}^{24}(t,\alpha \gamma ){\mathrm{Na}}^{23}$ reaction has been used to investigate the spins and decay modes of many of the levels in ${\mathrm{Na}}^{23}$ below an excitation energy of 6 MeV, as well as the multipole mixing ratios of the radiative transitions between these levels. $\gamma$ radiation was detected in NaI(Tl) detectors located at angles between 0 and 90°, while outgoing $\alpha$ particles were detected in an annular detector placed at 180° with respect to the beam direction. Two-parameter techniques were used to measure the $\alpha -\gamma$ coincidence spectra. Analysis of the resultant $\gamma$- ray angular correlations, when combined with already existing data, enabled the following unambiguous spin assignments to be made: 2.98-MeV level $J=\frac{3}{2}$, 3.68-MeV level $J=\frac{3}{2}$, 3.91-MeV level $J=\frac{5}{2}$. Limitations on the possible spins of the 4.78-, 5.38-, and 5.74-MeV levels were obtained. The results are discussed in terms of the Nilsson model for ${\mathrm{Na}}^{23}$.