Lifetime of metastable Ne2+ ions measured at a heavy-ion storage ring

The radiative lifetime of the 2s(2)2p(4) S-1(0) level in Ne2+ ions has been measured by time-resolved observations of one of the electric-dipole forbi dden decay branches, the magnetic dipole (M1) transition to the 2s(2)2p(4) P-3(1) level, on ions circulating in a heavy-ion storage ring. The result, a lifetime of 213 +/- 4 ms, agrees within the mutual 2 sigma errors with th at of a recent measurement using a radiofrequency ion trap, but is expected to suffer less from possible systematic error. It also compares very well with two calculations that have been semiempirically corrected for experime ntal transition energies.