Radiative lifetime measurement of 1S0 metastable state of Ar2+ using electrostatic ion beam trap

The radiative lifetime of the 3s23p41S0 metastable state of Ar2+ was measured using an electrostatic ion beam trap. The lifetime was obtained by measuring the number of photons emitted during the 1S0 → 3P1 magnetic dipole transition of Ar2+ as a function of the storage time. The wavelength of the photons was 311 nm. To correct for the collision-induced loss of Ar2+ ions in the trap, the storage lifetime of the Ar2+ beam was measured simultaneously by detecting Ar neutrals escaping from the trap. The obtained radiative lifetime was 157 ± 19 ms, which was comparable to previously reported theoretical and experimental values.