Initial evaluation of the NPL caesium fountain frequency standard

Author

Szymaniec, K. ; Chalupczak, W. ; Henderson, D.

Author_Institution

Nat. Phys. Lab., Teddington, UK

fYear

2003

fDate

4-8 May 2003

Firstpage

112

Lastpage

114

Abstract

An initial performance evaluation of the caesium fountain primary frequency standard at the NPL is reported. Improved magnetic shielding has resulted in the inhomogeneity of the C-field being below 1 nT and has enabled the observation of full-contrast Ramsey fringes. A direct evaluation of the fountain´s stability in comparison to a hydrogen maser is shown to agree with the short-term stability inferred from the signal-to-noise ratio. The stability is consistent with the limit set by the local oscillator. The measurement of the frequency bias due to cold collisions is described, together with the associated uncertainty.

Keywords

Zeeman effect; atomic clocks; atomic collisions; caesium; frequency stability; frequency standards; magnetic shielding; measurement uncertainty; C-field inhomogeneity; Cs; NPL caesium fountain frequency standard; Ramsey fringe; cold collision; fountain stability; frequency bias measurement; magnetic shielding; performance evaluation; signal-noise ratio; uncertainty evaluation; Atom optics; Atomic beams; Atomic measurements; Frequency; Laser beams; Laser excitation; Magnetic noise; Masers; Phase noise; Solenoids;

fLanguage

English

Publisher

ieee

Conference_Titel

Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, 2003. Proceedings of the 2003 IEEE International

ISSN

1075-6787

Print_ISBN

0-7803-7688-9

Type

conf

DOI

10.1109/FREQ.2003.1274998

Filename

1274998