List of atomic clocks

This is a list of some experimental laboratory atomic clocks worldwide.

Name	Operation date	Type	Accuracy	Location	Image
CS1 [1]	1969	Cs	7×10−15	Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
CS2 [2]	1985	Cs	1.2×10−14	Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
CS3	1988	Cs		Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
CS4	1992-2005	Cs		Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
CSF1 [3]	1999	Cs fountain	4×10−16	Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
CSF2 [4]	2009	Cs fountain	2×10−16	Physikalisch-Technische Bundesanstalt Braunschweig,   Germany
FOCS				Federal Institute of Metrology Wabern,   Switzerland
NPL-CsF2, Yb+ and Sr+ ion clocks, Sr lattice clock, 4 hydrogen masers [5] [6]				National Physical Laboratory Teddington, London,   United Kingdom
NIST Ion Clock	2025	Charged Al ion with Mg ion	5.5×10−19	NIST Boulder Laboratories Boulder, Colorado   United States [7]
NIST-F1 [8]		Cs fountain	3.1×10−16	NIST Boulder Laboratories Boulder, Colorado   United States [9]
NIST-F2 [10]		Cs fountain	1.1×10−16	NIST Boulder Laboratories Boulder, Colorado   United States [11]
USNO Alternate Master Clock				Schriever Air Force Base El Paso County, Colorado   United States [12]
WWV				WWVB Larimer County, Colorado   United States [13]
Department of Defense master clock				United States Naval Observatory Washington, D.C.   United States
18 cesium atomic clocks and 4 hydrogen maser clocks		Cs, H		National Institute of Information and Communications Technology Koganei,   Japan [14]
Optical lattice clock				University of Tokyo Bunkyō, Tokyo,   Japan [15] [16]
NMIJ-F1, NMIJ-F2 [17]		Cs fountain	4.7×10−16	National Metrology Institute of Japan Tokyo,   Japan
Optical clock [18]	2012	Ca ion		Hubei,   China
Caesium Beam Atomic Clock [19] [20]		Cs		Hong Kong Observatory Tsim Sha Tsui,   Hong Kong [21]
9 Agilent 5071A caesium clocks [22]		Cs	5×10−13	National Standard Time and Frequency Laboratory Taoyuan,   Taiwan [23]
KRISS-1 [24] [25]		Cs	1×10−14	Korea Research Institute of Standards and Science Daejeon,   South Korea
Caesium atomic clocks [26]		Cs		National Metrology Centre Queenstown,   Singapore
Five caesium clocks, one passive hydrogen maser, two active hydrogen masers [27]		Cs, H		National Physical Laboratory of India New Delhi,   India
DOST-PAGASA Juan Time [28]				Department of Science and Technology Taguig,   Philippines
Caesium clocks, Hydrogen Maser [29]		Cs		Indonesian Institute of Sciences Jakarta,   Indonesia
SOC: Space Optical Clock breadboard (Sr lattice clock) [30]		Sr lattice		European Space Agency Düsseldorf,   Germany Braunschweig,   Germany Birmingham,   United Kingdom Paris,   France Florence,   Italy Turin,   Italy Prague,   Czech Republic
Deep Space Atomic Clock [31]	2019-2021	Hg ion		Jet Propulsion Laboratory La Cañada Flintridge, California   United States
Caesium atomic clocks [32]		Cs		Laboratorium Czasu i Częstotliwości (CBK PAN) Borówiec,   Poland

References

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2. "Seit wann läuft die erste Atomuhr in der PTB?". Themenrundgänge / Fragen zur Zeit. Physikalisch-Technische Bundesanstalt. Archived from the original on 2012-11-27. Retrieved 2013-02-04.
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21. "Contact us". The Government of the Hong Kong Special Administrative Region. Retrieved 2013-02-11.
22. "Clocks and Time scales". National Time and Frequency Standard Laboratory. Retrieved 2013-02-14.
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24. "Development of Korea's First Primary Frequency Standard, 'KRISS-1'" (PDF). KRISS. Retrieved 2013-03-01.
25. Lee, Ho Seong; Kwon, Taeg Yong; Park, Sang Eon; Choi, Sang-Kyung; Park, Young-Ho (August 2004). "Research on Cesium Atomic Clocks at the Korea Research Institute of Standards and Science". Journal of the Korean Physical Society. 45 (2): 256–272. Archived from the original on 2016-03-04. Retrieved 2013-03-06.
26. "About SST". National Metrology Centre. Archived from the original on 2013-04-18. Retrieved 2013-03-01.
27. "Time and Frequency Metrology". CSIR-National Physical Laboratory. CSIR-National Physical Laboratory. Retrieved 2023-03-25.
28. "With PST, "Filipino time" is now "on time"". Department of Science and Technology. Retrieved 2014-06-07.
29. "Time Standard". Indonesian Institute of Sciences. Archived from the original on 2016-01-21. Retrieved 2016-06-22.
30. "Space Optical Clock". Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf. Retrieved 2017-01-30.
31. "Deep Space Atomic Clock". NASA's Jet Propulsion Laboratory. NASA. 27 April 2015. Retrieved 2015-10-28.
32. "Uruchomiono najdokładniejszy zegar atomowy w Polsce. Nie straci nawet sekundy przez 200 mln lat". wyborcza.pl. Retrieved 2018-03-24.