Laser-induced photoionization in the dark space of a hollow cathode

Abstract

We describe an experimental set-up to measure fast current pulses generated via laser-induced photoionization in the dark space of a high-current hollow cathode. With suitably matched delay lines reflections disturbing the signals are avoided without debasing the response function of the system. An advanced theoretical model allows the determination of absolute photoionization cross sections and number densities exploiting the time-resolved shape of the current pulses. Experiment and theory have been tested on the autoionizing Cu I at 458.824 nm. We measured a cross section for this transition with and a density of the lower level of .