Magnetic Moment of the extremely proton rich nucleus $^{23}$Al

We have studied the spin parity of $^{23}$Al through the measurement of the magnetic moment by the $\beta $-NMR method. The experiment was performed at RIKEN/ RIPS. The polarized $^{23}$Al nuclei were produced through the 135-$A $MeV $^{28}$Si and Be collisions, and were separated by the RIPS separator and RF deflector. The NMR was observed by the $\beta $-ray asymmetry change. From the resonance frequency, we determined the $g-$factor of $^{23}$Al as $\vert g\vert (^{23}$Al) = 1.56(9). From the comparison between the present result and the shell model calculation, it was found that $^{23}$Al had the normal spin parity of 5/2$^{+}$. The magnetic moment was determined as $\vert \mu \vert (^{23}$Al) = 3.89(22) $\mu _N $. The level inversion between $d_{5/2} $ and $s_{1/2} $ states was not seen in the structure of $^{23}$Al.