Mass determination near N=20 for Al and Na isotopes

We report on the mass measurements of Na-31,Na-32 and Al-29,Al-34,Al-35, performed with the TITAN Penning trap mass spectrometer at TRIUMF. The mass excesses were found to be 12246(14) and 18638(37) keV for Na-31,Na-32 and -18207.77(37), -3000.5(29), and -223.7(73) keV for Al-29,Al-34,Al-35, respectively. Our measurements confirm the observation of a crossover in the two-neutron separation energies of Mg-33 and Al-34. We did not observe the recently reported, long-lived, isomeric state of Al-34, but, based on the previously measured half-lives, the mass value of the ground state was determined.