cid c45d30272a761abc95751c95ffd486ca89b744493c3f9d486219e6bf34f26fa4 · original · open access · via wikipedia
Title: Caesium standard Authors: Venue: Wikipedia Year: unknown Canonical: wiki:caesium-standard URL: https://en.wikipedia.org/wiki/Caesium_standard Collector: wikipedia OA: true ABSTRACT The caesium standard is a primary frequency standard in which the photon absorption by transitions between the two hyperfine ground states of caesium-133 atoms is used to control the output frequency. The first caesium clock was built by Louis Essen in 1955 at the National Physical Laboratory in the UK and promoted worldwide by Gernot M. R. Winkler of the United States Naval Observatory.