High intensity source for cold atomic hydrogen and deuterium beams

A source of highly dissociated, intense, cold hydrogen and deuterium atomic beams to be used as a dissociator in polarized gas targets for storage ring experiments has been developed. This dissociator is based on a plasma source which couples a 2.45 GHz surface wave to the discharge. At the end of the discharge tube a cold atomic beam is formed by means of a cooled nozzle. The entire system has been optimized to obtain a beam with a high atomic fraction and long-term stable reproducible operation. We measured a high degree of dissociation of more than 70% at gas throughputs up to 3 mbar ℓ/s for both hydrogen and deuterium, corresponding to an atomic flow rate of 1.2×1020 s−1. Excellent long-term stability has been achieved. We also studied quantitatively the effect of recombination of atoms on the nozzle surface for various materials.