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 forbidden 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 that 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 experimental transition energies.