Electric quadrupole moment of 31Al

Abstract The electric quadrupole moment Q for the ground state of 31 Al ( I π  = 5/2 + ) was measured by means of the β ray-detected nuclear quadrupole resonance. A spin-polarized radioactive beam of 31 Al was produced in the projectile-fragmentation reaction of a 40 Ar beam on a 93 Nb target. For the Q moment measurement, we developed a new radio-frequency application system to induce the spin reversal.