The JPL Trapped Ion Frequency Standard Development
Abstract
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 of this locked oscillator is currently sigma(y) (tau) = 4.4 x 10(-12) / square root of tau for 20 < tau < 320 seconds, indicating better short term stability than the best commercial cesium standards by almost a factor of two. This first result was achieved without magnetic shielding and without regulation of ion number.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1987
- Accession Number
- ADA515560
Entities
People
- G. J. Dick
- J. D. Prestage
- L. Maleki
Organizations
- California Institute of Technology