Jacques Vanier and Claude Audoin 2005 Metrologia 42 S31 doi:10.1088/0026-1394/42/3/S05
Jacques Vanier1 and Claude Audoin2
Show affiliationsThe caesium beam frequency standard using the separated oscillatory field technique proposed by Ramsey in 1950 has seen intensive development over the last fifty years. Its practical implementation as a primary time standard made possible the realization of the second with a precision better than that obtained by means of astronomical measurements and provided the basis for its redefinition in terms of atomic properties in 1967. This paper describes the basic principles underlying the operation of such atomic standards, reviews the progress made during the last fifty years since its invention, and provides an update on the state-of-the-art accuracy and frequency stability achieved today in this field.
Issue 3 (June 2005)
Received 16 December 2004
Published 7 June 2005
Jacques Vanier and Claude Audoin 2005 Metrologia 42 S31
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