Improved Timekeeping Using Advanced Trapped-Ion Clocks
CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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Timekeeping requires practical continuously operating frequency standards with exceptional long-term stability. JPL mercury linear ion trap standards LITS operate continuously with short-term stability to 2.0 x 10exp -14 and long-term stability limited by remaining sensitivity to the second-order Doppler shift, which varies with ion number fluctuations. In this paper, we report measurements in a 12-pole trap showing a greater than twenty-fold sensitivity reduction to all parameters affecting the Second-Order Doppler Shift. This advance should further improve practical ground-based ion standard stability to the 1 x 10exp -16 level and allow significant engineering simplifications enabling small high performance flight standards.
- Test Facilities, Equipment and Methods