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  2. Caesium standard - Wikipedia

    en.wikipedia.org/wiki/Caesium_standard

    A caesium atomic fountain used as part of an atomic clock. 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.

  3. Atomic clock - Wikipedia

    en.wikipedia.org/wiki/Atomic_clock

    The main variety of atomic clock uses caesium atoms cooled to temperatures that approach absolute zero. The primary standard for the United States, the National Institute of Standards and Technology (NIST)'s caesium fountain clock named NIST-F2, measures time with an uncertainty of 1 second in 300 million years (relative uncertainty 10 −16 ...

  4. Chip-scale atomic clock - Wikipedia

    en.wikipedia.org/wiki/Chip-scale_atomic_clock

    Like other caesium atomic clocks, the clock keeps time by a precise 9.192631770 GHz microwave signal emitted by electron spin transitions between two hyperfine energy levels in atoms of caesium-133. A feedback mechanism keeps a quartz crystal oscillator on the chip locked to this frequency, which is divided down by digital counters to give 10 ...

  5. List of atomic clocks - Wikipedia

    en.wikipedia.org/wiki/List_of_atomic_clocks

    18 cesium atomic clocks and 4 hydrogen maser clocks Cs, H National Institute of Information and Communications Technology; Koganei, ...

  6. NIST-F1 - Wikipedia

    en.wikipedia.org/wiki/NIST-F1

    NIST-F1 is a cesium fountain clock, a type of atomic clock, in the National Institute of Standards and Technology (NIST) in Boulder, Colorado, and serves as the United States' primary time and frequency standard. The clock took fewer than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of the Time and ...

  7. NIST-F2 - Wikipedia

    en.wikipedia.org/wiki/NIST-F2

    NIST physicists Steve Jefferts (foreground) and Tom Heavner with the NIST-F2 cesium fountain atomic clock, a civilian time standard for the United States. NIST-F2 is a caesium fountain atomic clock that, along with NIST-F1, serves as the United States' primary time and frequency standard. [1] NIST-F2 was brought online on 3 April 2014. [1] [2]

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  9. Caesium atomic clock - Wikipedia

    en.wikipedia.org/?title=Caesium_atomic_clock&...

    Retrieved from "https://en.wikipedia.org/w/index.php?title=Caesium_atomic_clock&oldid=426488587"