Lifetime Measurement of the 8s Level in Francium
  We measure the lifetime of the 8s level on a magneto-optically trapped sample of ^{210}Fr atoms with time-correlated single-photon counting. The 7P_{1/2} state serves as the resonant intermediate level for two-photon excitation of the 8s level completed with a 1300 nm laser. Analysis of the fluorescence decay through the the 7P_{3/2} level gives 53.30 +- 0.44 ns for the 8s level lifetime. 
E. Gomez (1), L. A. Orozco (2), A. Perez Galvan (2), G. D. Sprouse (1)   ((1) Dept. of Physics and Astronomy, SUNY Stony Bro...