High-precision half-life determination of O-14 via direct beta counting

The half-life of the superallowed Fermi beta(+) emitter O-14 was determined to high precision via a direct beta counting experiment performed at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. The result, T-1/2(O-1(4)) = 70619.2(76) ms, is consistent with, but is more precise than, the world average obtained from 11 previous measurements. Combining the O-14 half-life deduced in the present work with the previous most precise measurements of this quantity leads to a reduction in the overall uncertainty, by nearly a factor of 2. The new world average is T-1/2(O-1(4)) = 70619.6(63) ms with a reduced chi(2) value of 0.87 obtained from 8 degrees of freedom.