This is a list of some experimental laboratory atomic clocks worldwide.
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Name | Operation date | Type | Accuracy | Location | Image |
---|---|---|---|---|---|
CS1 [1] | 1969 | Cs | 7×10−15 | ||
CS2 [2] | 1985 | Cs | 1.2×10−14 | ![]() | |
CS3 | 1988 | Cs | |||
CS4 | 1992-2005 | Cs | ![]() | ||
CSF1 [3] | 1999 | Cs fountain | 4×10−16 | ||
CSF2 [4] | 2009 | Cs fountain | 2×10−16 | ||
FOCS | |||||
NPL-CsF2, Yb+ and Sr+ ion clocks, Sr lattice clock, 4 hydrogen masers [5] [6] | |||||
NIST-F1, [7] | Cs fountain | 3.1×10−16 | ![]() | ||
NIST-F2 [9] | Cs fountain | 1.1×10−16 | ![]() | ||
USNO Alternate Master Clock | ![]() ![]() | ||||
WWV | |||||
Department of Defense master clock | ![]() | ||||
18 cesium atomic clocks and 4 hydrogen maser clocks | Cs, H | ||||
Optical lattice clock | |||||
NMIJ-F1, NMIJ-F2 [16] | Cs fountain | 4.7×10−16 | |||
Optical clock [17] | 2012 | Ca ion | |||
Caesium Beam Atomic Clock [18] [19] | Cs | ||||
9 Agilent 5071A caesium clocks [21] | Cs | 5×10−13 | |||
KRISS-1 [23] [24] | Cs | 1×10−14 | ![]() | ||
Caesium atomic clocks [25] | Cs | ||||
Five caesium clocks, one passive hydrogen maser, two active hydrogen masers. [26] | Cs, H | ||||
DOST-PAGASA Juan Time [27] | |||||
Caesium clocks, Hydrogen Maser [28] | Cs | ||||
SOC: Space Optical Clock breadboard (Sr lattice clock) [29] | Sr lattice |
| ![]() | ||
Deep Space Atomic Clock [30] | 2019-2021 | Hg ion | |||
Caesium atomic clocks [31] | Cs |
International Atomic Time is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. TAI is a weighted average of the time kept by over 450 atomic clocks in over 80 national laboratories worldwide. It is a continuous scale of time, without leap seconds, and it is the principal realisation of Terrestrial Time. It is the basis for Coordinated Universal Time (UTC), which is used for civil timekeeping all over the Earth's surface and which has leap seconds.
Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the Bureau International des Poids et Mesures (BIPM) was established by the Metre Convention. This has evolved into the International System of Units (SI) as a result of a resolution at the 11th General Conference on Weights and Measures (CGPM) in 1960.
The Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of the Federal Republic of Germany, with scientific and technical service tasks. It is a higher federal authority and a public-law institution directly under federal government control, without legal capacity, under the auspices of the Federal Ministry for Economic Affairs and Climate Action.
DCF77 is a German longwave time signal and standard-frequency radio station. It started service as a standard-frequency station on 1 January 1959. In June 1973 date and time information was added. Its primary and backup transmitter are located at 50°0′56″N9°00′39″E in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. The transmitter generates a nominal power of 50 kW, of which about 30 to 35 kW can be radiated via a T-antenna.
Hitlers Bombe is a nonfiction book by the German historian Rainer Karlsch published in March 2005, which claims to have evidence concerning the development and testing of a possible "nuclear weapon" by Nazi Germany in 1945. The "weapon" in question is not alleged to be a standard nuclear weapon powered by nuclear fission, but something closer to either a radiological weapon or a hybrid-nuclear fusion weapon. Its new evidence is concerned primarily with the parts of the German nuclear energy project under Kurt Diebner.
The Technical University of Braunschweig, commonly referred to as TU Braunschweig, is the oldest Technische Universität in Germany. It was founded in 1745 as Collegium Carolinum and is a member of TU9, an incorporated society of the most renowned and largest German institutes of technology. It is commonly ranked among the top universities for engineering in Germany. TU Braunschweig's research profile is very interdisciplinary, but with a focus on aeronautics, vehicle engineering including autonomous driving and electric mobility, manufacturing, life sciences, and metrology. Research is conducted in close collaboration with external organizations such as the German Aerospace Center (DLR), Helmholtz Centre for Infection Research, several Fraunhofer Institutes, and Germany's national metrology institute (PTB), among many others. As one of very few research institutions of its type in the world, the university has its own research airport.
Various governments require a certification of voting machines.
Werner Gitt is a German engineer and young earth creationist. Before retirement, he was Head of the Department of Information Technology at Physikalisch-Technische Bundesanstalt.
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 less than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of the Time and Frequency Division of NIST's Physical Measurement Laboratory.
The time zone in Germany is Central European Time and Central European Summer Time. Daylight saving time is observed from the last Sunday in March to the last Sunday in October. The doubled hour during the switch back to standard time is named 2A and 2B.
The cryogenic current comparator (CCC) is used in the electrical precision measurements to compare electric currents with the highest accuracy. This device exceeds the accuracy of other current comparators around several orders of magnitude. It is used in electrical metrology for exact comparative measurements of electric resistances or the amplification and measurement of extremely small electric currents.
NIST-F2 is a caesium fountain atomic clock that, along with NIST-F1, serves as the United States' primary time and frequency standard. NIST-F2 was brought online on 3 April 2014.
The Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m. b. H., abbreviated BESSY, is a research establishment in the Adlershof district of Berlin. Founded on 5 March 1979, it currently operates one of Germany's 3rd generation synchrotron radiation facilities, BESSY II. Originally part of the Leibniz Association, BESSY now belongs to the Helmholtz-Zentrum Berlin.
Two-way satellite time and frequency transfer (TWSTFT) is a high-precision long distance time and frequency transfer mechanism used between time bureaux to determine and distribute time and frequency standards.
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:
The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, , the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.
A quantum clock is a type of atomic clock with laser cooled single ions confined together in an electromagnetic ion trap. Developed in 2010 by physicists at the U.S. National Institute of Standards and Technology, the clock was 37 times more precise than the then-existing international standard. The quantum logic clock is based on an aluminium spectroscopy ion with a logic atom.
Leonard Cutler (1928–2006), also known as Leonard S. Cutler, was a pioneer and authority on ultra-precise timekeeping devices and standards, and was well known for his work with quantum-mechanical effects. He was the co-inventor of the HP5060A Cesium Beam Clock, its successor the HP 5071A, and the two-frequency laser inferometer. He has also been praised for his crucial contributions to the design of the Allen Telescope Array.
Pulse programming in the field of experimental physics refers to engineering sinusoidal electromagnetic waveforms to have programmable frequencies, phases, and amplitudes. The main techniques and terminology arose in the study of nuclear magnetic resonance (NMR) during the 1970s, but has since been adopted in many other experimental settings, usually associated with quantum computing experiments. These include electron spin resonance (ESR), trapped ions, quantum dots, the phase/flux/charge across a superconducting junctions, and many other quantum bit implementations. Traditionally, pulse programmers were built using hard-wired analog electronics to produce a fixed sequence of waveforms, but modern pulse programmers make use of direct digital synthesis programmable electronics controlled by a personal computer to make precisely reproducible sequences.
Mobile metering is a technology which enables mobile recording of metering data. While railway companies such as the German Deutsche Bahn have been using this technology for years in their trains, it is now also being used for recording the charging transactions of electric vehicles (EVs). Weil/Neumann. "Vergleichende Betrachtung der Sicherheitskonzepte von Mobile Metering und Smart Meter Gateways". Physikalisch-technische Bundesanstalt . 125: 53–58.
Pascal Del'Haye is a German physicist specializing in integrated photonics. He is heading the Microphotonics Research Group at the Max Planck Institute for the Science of Light.