Title :
Accuracy evaluation of a cesium fountain primary frequency standard at NIST
Author :
Meekhof, D.M. ; Jefferts, S.R. ; Shirley, J.H. ; Parker, T.E.
Author_Institution :
Time & Frequency Div., Nat. Inst. of Stand. & Technol., Boulder, CO, USA
Abstract :
Since November of 1998, we have performed five frequency uncertainty evaluations on NIST F-1, our laser-cooled cesium fountain. The results from the latest evaluation have a statistical uncertainty of 1.4/spl times/10/sup -15/ and an uncorrected bias of 0.7/spl times/10/sup -15/. The results have been reported to the BIPM for inclusion in TAI, making this clock one of two cesium fountain clocks used as primary standards in the world. We will present an overview of the evaluations and their uncertainties.
Keywords :
atomic clocks; cesium; frequency stability; frequency standards; laser cooling; measurement uncertainty; radiation pressure; Cs; NIST F-1 laser-cooled cesium fountain; Ramsay microwave cavity; TAI time; accuracy evaluation; atomic fountain primary frequency standard; blackbody radiation shift; cesium fountain clocks; frequency uncertainty evaluation; gravitational redshift; optical molasses; second-order Zeeman shift; spin exchange; statistical uncertainty; uncorrected bias; Acceleration; Atom lasers; Atom optics; Atomic beams; Clocks; Frequency; Laser beams; NIST; Optical attenuators; Uncertainty;
Conference_Titel :
Precision Electromagnetic Measurements Digest, 2000 Conference on
Conference_Location :
Sydney, NSW, Australia
Print_ISBN :
0-7803-5744-2
DOI :
10.1109/CPEM.2000.851001
