Stability measurements between Hg/sup +/ lite 12-pole clocks

We describe frequency stability measurements of two Hg-ion clocks based upon linear 12-pole shuttle ion traps. The inter-comparison was carried out over several multi-day intervals with the short-term stability of each clock better than 2/spl times/10/sup -13/ at 1 second. Longer-term stability as good as 3/spl times/10/sup -16/ was demonstrated for these clocks.