Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

Photoionization of a laser-cooled and compressed atomic beam from a high-flux thermal source can be used to create a high-brightness ion beam for use in focused-ion-beam instruments. Here we show using calculations and Doppler cooling simulations that an atomic rubidium beam with an equivalent brightness of 2.1×107 A/(m2 sr eV) can be created using a compact 5 cm long two-dimensional magneto-optical compressor. If this can be conserved during the photoionization process, this leads to an ion beam brightness an order of magnitude higher than produced by a liquid metal ion source. The source is also capable of producing a flux of 6.2×109 s-1 that results in a substantial beam current of 1 nA once fully ionized