Spin, Hyperfine Structure, and Nuclear Magnetic Dipole Moment of 23-secNa21

The spin and hyperfine structure of 23-sec ${\mathrm{Na}}^{21}$, the mirror nucleus to ${\mathrm{Ne}}^{21}$, have been measured by the atomic-beam magnetic-resonance technique. The ${\mathrm{Na}}^{21}$ was produced by the reaction ${\mathrm{Mg}}^{24}(p, \alpha ){\mathrm{Na}}^{21}$. The target material in the form of a powder was bombarded in an oven in the resonance apparatus. If the oven was heated to about 450°C, the ${\mathrm{Na}}^{21}$ escaped from the Mg in sufficient quantity to make a useful atomic beam. Both $\Delta F=0\mathrm{}$ and $\Delta F=1\mathrm{}$ resonances were observed, and the final values are $I=\frac{3}{2}$, $\Delta \nu =1906.466\mathrm{}\pm 0.021$ Mc/sec. Comparison with ${\mathrm{Na}}^{23}$ yields ${\mu }_I=2.386\mathrm{}12\pm 0.00010$ nm (diamagnetically corrected). The results are discussed in terms of the current nuclear theories.