| Improved Timekeeping Using Advanced Trapped-Ion Clocks |
Dec-1999 |
9 pages |
| Authors:
R L Tjoelker; L Maleki; J D Prestage; 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 10(exp -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 ... |
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| The JPL Hg+ Extended Linear Ion Trap Frequency Standard: Status, Stability, and Accuracy Prospects |
Dec-1996 |
10 pages |
| Authors:
R L Tjoelker; L Maleki; J D Prestage; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| 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 ... |
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| Local Oscillator Induced Degradation of Medium-Term Stability in Passive Atomic Frequency Standards |
Dec 1990 |
23 pages |
| Authors:
G J Dick; J D Prestage; C A Greenhall; L Maleki; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| As the performance of passive atomic frequency standards improves, a new limitation is encountered due to frequency fluctuations in an ancillary local oscillator (L.O.). The effect is due to time variation in the gain of the feedback which compensates L.O. frequency fluctuations. The high performance promised by new microwave and optical trapped ion standard may be severely compromised by this effect. We present un anabsk of this performance limitation for ... |
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| Ultra-Stable Hg+ Trapped Ion Frequency Standard |
Dec 1990 |
16 pages |
| Authors:
J D Prestage; G J Dick; L Maleki; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| We are developing a fieldable trapped ion frequency standard based on (199) Hg(+) ions confined in a hybrid rf/dc linear ion trap. This trap permits storage of large numbers of ions with reduced susceptibility to the second-order Doppler effect caused by the rf confining fields. In preliminary measurements we have obtained a stability of 2-3/10(-15) for 10,000 second averaging times. These measurements were carried out with a 120 mHz wide ... |
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| New Ion Trap for Frequency Standard Applications |
Dec-1988 |
8 pages |
| Authors:
L Maleki; J D Prestage; G J Dick; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| We have designed and built a novel linear ion trap which permits storage of a large number of ions with reduced susceptibility to the second order Doppler effect caused by the RF confining fields. This new trap should store about 20 times the number of ions as a conventional RF trap with no corresponding increase in second order Doppler shift from the confining field. Other comparisons to standard RF ion ... |
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| The JPL Trapped Ion Frequency Standard Development |
Dec 1987 |
14 pages |
| Authors:
J D Prestage; G J Dick; L Maleki; CALIFORNIA INST OF TECHNOLOGY PASADENA CA JET PROPULSION LAB
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| Mercury 199 Ions are confined in an RF trap and state-selected by use of optical pumping with 194 nm UV light from a (202)Hg discharge lamp. Absorption of microwave radiation at the hyperfine frequency (40.5 GHz) is signaled by atomic fluorescence of the UV light. The frequency of a 40.5 GHz oxcillator is locked to a 1.6 Hz wide atomic absorption line of the trapped ions. The measured Allan variance ... |
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| Frequency and Time Standards Based on Stored Ions |
Nov-1984 |
11 pages |
| Authors:
J D Prestage; D J Wineland; J J Bollinger; W M Itano; J C Bergquist; NATIONAL BUREAU OF STANDARDS BOULDER CO
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| The method of ion storage provided a basis for excellent time and frequency standards. This is due to the ability to confine ions for long periods of time without the usual perturbations associated with confinement (e.g. wall shifts). In addition, Doppler effects can be greatly suppressed. The use of stored ions for microwave frequency standards and the future possibilities for an optical frequency standard based on stored ions are addressed. ... |
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| Mercury Trapped-Ion Frequency Standard for the Global Positioning System |
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11 pages |
| Authors:
R L Tjoelker; B Tucker; G Sprague; S Sepulveda; T Radey; N Raouf; J D Prestage; L Maleki; L Lim; R Hamell; R Glaser; S Chung; E Burt; B Young; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| We report on progress towards the development of a small, low-mass and -power, high-stability mercury trapped-ion frequency standard for the Global Positioning System. The design performance goal is a frequency stability reaching into the 10(-16) range using technologies that allow for more than 10 years of continuous operational life. Key features include using a multi-pole ion trap to minimize sensitivity to ion-number-dependent effects and a nitrogen buffer gas for long ... |
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| Liter Sized Ion Clock with 10 (exp -15) Stability |
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6 pages |
| Authors:
L Lim; L Maleki; J D Prestage; S Chang; T Le; CALIFORNIA INST OF TECHNOLOGY PASADENA JET PROPULSION LAB
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| We have recently completed a breadboard ion-clock physics package based on Hg ions shuttled between a quadrupole and a 16-pole rf trap. With this architecture we have demonstrated short-term stability 2-3x10-13 at 1 second, averaging to 10-15 at 1 day. This development shows that Hmaser quality stabilities can be produced in a small clock package, comparable in size to an ultra-stable quartz oscillator required for holding 1-2x10-13 at 1 second. ... |
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