Spin and magnetic moment of25Na by ?-radiation detected optical pumping

25Na (T1/2 = 60 sec) has been produced in a22Ne target by the (α,p) reaction and polarized by means of spin-exchange scattering with optically pumped87Rb. The asymmetry in the β decay of polarized nuclei served to detect rf transitions between hfs Zeeman levels of the atomic ground state, yielding spinI = 5/2 and hyperfine splitting ΔW= 2648.5(3.0) MHz, from which the magnetic moment μI = 3.683(4)nm (corrected for diamagnetism) was deduced.