Laser cooling and photoionization of alkali atoms

We carry out photoionization experiments on laser-cooled alkali atoms by ir radiating rubidium and cesium magneto-optical traps (MOTs) with a photoioni zing laser beam. Analysis of the loading behavior of the traps allows us to determine photoionization cross-sections for the first excited state of ru bidium and cesium based on a trap load/loss model. In addition, our experim ental findings reveal systematic peculiarities, which can be ascribed to th e low temperature of the atomic samples under investigation. (C) 2000 Publi shed by Elsevier Science B.V. All rights reserved.