Precision lifetime measurements using laser excitation of a fast atomic beam

Abstract

We employ resonant laser excitation of a fast atomic beam to measure excited state lifetimes by observing the decay-in-flight of the emitted fluorescence. Our program includes lifetime measurements of the low lying p states in alkali and alkali-like systems. This work was initiated by the motivation to test the atomic many-body-perturbation theory that is necessary for interpretation of parity nonconservation experiments in cesium. We report new measurements of the 6p 2 P 1 2 and 6p 2 P 3 2 state lifetimes in the 133Cs atom to be 34.934 ± 0.094 ns and 30.499 ± 0.070 ns respectively. With minor changes to the apparatus, we have extended our measurement capabilities to include the 2p 2 P 1 2 , 3 2 states of lithium. We present comparisons between measurements and relativistic calculations of atomic transition matrix elements.