JPL Hg+ Extended Linear Ion Trap Frequency Standard: Status, Stability, and Accuracy Prospects

摘要

Microwave frequency standards based on room temperature 199Hg+ ions in a Linear Ion Trap (LITS) presently achieve a signal-to-noise and line-Q- inferred short-term frequency stability of sigma sub y (tau) = 2x10E(exp - 14)/tau(exp 1/2). Long-term stability has been measured for averaging intervals up to 5 months with apparent sensitivity to variations in ion number/temperature limiting the flicker floor to about 5x10E-16 at 100,000 seconds. A two-segment version of the linear ion trap (LITE) has also recently demonstrated excellent frequency stability for measurement intervals up to one week. Nearly an order of magnitude improvement in long-term stability compared to the LITS is expected since this trap configuration operates with reduced linear ion density during the microwave interrogation period.