Metastable level lifetimes from electron-shelving measurements with ion clouds and single ions

摘要

The lifetime of the 3d^2D_5/2-level in singly-ionized calcium has beenmeasured by the electron-shelving technique on different samples of rf trappedions. The metastable state has been directly populated by exciting thedipole-forbidden 4S_1/2 - 3D_5/2 transition. In ion clouds, the naturallifetime of this metastable level has been measured to be (1095+-27) ms. Forthe single-ion case, we determined a lifetime of (1152+-20) ms. The1sigma-error bars at the 2%-level have different origins for the two kinds ofexperiments: data fitting methods for lifetime measurements in an ion cloud andcontrol of experimental parameters for a single ion. De-shelving effects areextensively discussed. The influence of differing approaches for the processingof the single-ion quantum jump data on the lifetime values is shown. Comparisonwith recent measurements shows excellent agreement when evaluated from a givenmethod.