β-decay of the neutron-rich nucleus 18N

The β-decay of 18N has been studied using β-n and β-γ coincidence methods. The 18N ions were produced by the fragmentation of the E/A=68.8 MeV 22Ne beam on a thick beryllium target. A newly constructed neutron detector system with wide energy detection range and low-energy detection threshold was used. The 619 ± 2 ms half-life of the 18N β-decay was found to be in very good agreement with the previous measurements. Transitions to 11 β-delayed neutron emitting states in 18O have been observed with a total branching ratio of 6.98 ± 1.46%. The Gamow-Teller β-decay strengths of 18N to these levels were deduced and compared with the shell model calculations. The intensities of the strong γ-ray transitions in 18O were found to be consistent with recent work