Performance of the PARCS testbed cesium fountain frequency standard

A cesium fountain frequency standard has been developed as a ground testbed for the PARCS (primary atomic reference clock in space) experiment - an experiment intended to fly on the International Space Station. We report on the performance of the fountain and describe some of the implementations motivated in large part by flight considerations, but of relevance for ground fountains. In particular, we report on a new technique for delivering cooling and trapping laser beams to the atom collection region, in which a given beam is recirculated three times effectively providing much more optical power than traditional configurations. Allan deviations down to 10^-15 have been achieved with this method.