Lifetimes of the 9s and 8p levels of atomic francium

We use time-correlated single-photon counting techniques on a sample of ²¹⁰Fr atoms confined and cooled in a magneto-optical trap to measure the lifetimes of the 9S_1∕2, 8P_3∕2, and 8P_1∕2 excited levels. We populate the 9S_1∕2 level by two-photon resonant excitation through the 7P_1∕2 level. The direct measurement of the 9S_1∕2 decay through the 7P_3∕2 level at 851 nm gives a lifetime of 107.53±0.90 ns. We observe the decay of the 9S_1∕2 level through the 8P_3∕2 level at 423 nm and the 8P_1∕2 level at 433 nm down to the 7S_1∕2 ground level, and indirectly determine the lifetimes of these to be 83.5±1.5 ns and 149.3±3.5 ns, respectively.