Cesium Beam Primary Frequency Standards at NRC

R.J. Douglas and J.S. Boulanger

Abstract:	The accuracy and long-term stability of time scales are established and maintained by reference to the primary frequency standards built and operated by national standards laboratories. The internationally accepted definition of the second is the specification for these cesium beam primary frequency standards. The experience of NRC in continuously operating such standards as clocks (28 clock-years) is summarized, and their capabilities are discussed. Developments that permit better monitoring of clock parameters are described. Possible evolutionary changes to Cs beam clock design are presented and the absence of dramatic improvements to accuracy is discussed. The use of laser-cooled atomic beams is examined. It appears applicable as the source of slow atoms required to implement Zacharias's dream of a fountain atomic beam with a resonance linewidth of less than 500mHz, and (for Cs) an accuracy approaching parts in 10^16.
Published in:	Proceedings of the 17th Annual Precise Time and Time Interval Systems and Applications Meeting December 3 - 5, 1985 DuPont Plaza Hotel Washington, DC
Pages:	189 - 200
Cite this article:	Douglas, R.J., Boulanger, J.S., "Cesium Beam Primary Frequency Standards at NRC," Proceedings of the 17th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1985, pp. 189-200.
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