Atomic clock - Wikipedia
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 ...
Caesium standard - Wikipedia
Caesium atomic clocks are one of the most accurate time and frequency standards, and serve as the primary standard for the definition of the second in the International System of Units (SI), the modern metric system.
Quantum mechanics - Cesium Clock, Timekeeping, Accuracy
2024年11月22日 · The cesium clock is the most accurate type of clock yet developed. This device makes use of transitions between the spin states of the cesium nucleus and produces a frequency which is so regular that it has been adopted for establishing the time standard. Like electrons, many atomic nuclei have spin.
How Does a Practical Cesium Atomic Clock Work? - HowStuffWorks
To create a clock, cesium is first heated so that atoms boil off and pass down a tube maintained at a high vacuum. First they pass through a magnetic field that selects atoms of the right energy state; then they pass through an intense microwave field.
NIST’s Cesium Fountain Atomic Clocks | NIST - National Institute …
2009年8月26日 · The combination of laser cooling and the fountain design allows the atomic fountain clock to observe cesium atoms for longer periods compared to traditional atomic beam clocks, and thus achieve its unprecedented accuracy. Traditional cesium clocks measure room-temperature atoms moving at several hundred meters per second.
NIST-F1 - Wikipedia
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 ...
5071A Cesium Primary Time and Frequency Standard
The 5071A is the most accurate commercial atomic clock available. It has an accuracy of less than 5E−13 under all environmental conditions and no deterministic frequency drift. The capabilities and reliability of the 5071A make it the single largest contributor of cesium clocks—more than half of all contributing clocks—to Coordinated ...
Introducing the World’s Most Precise Clock - IEEE Spectrum
2014年9月30日 · Cesium clocks, which are essentially very precise oscillators, use microwave radiation to excite electrons and get a fix on a frequency that’s intrinsic to the cesium atom.
Optical Clocks: The Future of Time | NIST - National Institute of ...
2024年8月22日 · The best of these clocks are now 100 times more accurate and stable than cesium fountain clocks. And they are still improving, as physicists build better lasers and find ways to super-cool clock components and package them in tighter vacuum chambers, minimizing vibrations and unwanted collisions with air particles.
Beams of Atoms: The First Atomic Clocks | NIST - National …
2024年8月22日 · Since the 1950s, beam clocks have ticked off the world’s seconds and given humanity an accurate and reliable foundation for global timekeeping. Indeed, the first practical atomic clocks were beam clocks. They were based on cesium, a soft, gold-colored metal found in the leftmost column of the periodic table.
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