Absolute photoionization cross sections of the Cs 7D3/2level measured by use of fluorescence reduction

A simple technique for measuring absolute photoionization cross sections σ of excited atoms has been applied to the 7$D_{3/2}$ level in Cs. Past experiments on excited-state cross sections have relied on measurements of the total number of ions or photoelectrons produced by photoionization to deduce σ. Our technique is novel in that it utilizes the simple measurement of the reduction in the excited-atom fluorescence due to photoionization to find σ. We report measurements of cross sections at six different photon energies.