Properties of a rubidium isotope ion beam extracted from a laser ion source

An atomic beam of rubidium was isotope selectively photoionized by irradiating the fundamental output of a Ti:sapphire laser and the third harmonics of a Nd:YAG laser. The resultant rubidium ions were extracted and collimated with electrodes as a laser ion source. Ion images of 85Rb and 87Rb were observed on the phosphor screen of a microchannel plate (MCP). It was possible to optimize the observed beam spot size by varying the potential applied to the electrodes. The ion energy corresponded to the potential of the laser-irradiated position between the electrodes. The ion source has potential use as an isotope-selective tool for material processing. (author)