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NIST atomic fountain clock gets much better with time
September 26, 2005The world's best clock, NIST-F1, has been improved over the past few years and now measures time and frequency more than twice as accurately as it did in 1999 when first used as a national standard, physicists at the National Institute of Standards and Technology (NIST) report.
The improved version of NIST-F1 would neither gain nor lose one second in 60 million years, according to a paper published online Sept. 13 by the journal Metrologia.* NIST-F1 uses a fountain-like movement of cesium atoms to determine the length of the second. The clock measures the natural oscillations of the atoms to produce more than 9 billion "ticks" per second. These results then contribute to the international group of atomic clocks that define the official world time. NIST-F1 has been formally evaluated 15 times since 1999; in its record performance, it measured the second with an uncertainty of 0.53 �— 10-15
The improved accuracy is due largely to three factors, according to Tom Parker, leader of the NIST atomic standards research group. First, better lasers, software and other components have made the entire NIST-F1 system much more reliable and able to operate for longer periods of time. Second, the atoms in the cesium vapor are now spread out over a much larger volume of space, reducing the frequency shifts caused by interactions among the atoms. (The formerly round cloud of atoms is now shaped like a short cigar.) Third, scientists are now better able to control magnetic fields within the clock and quantify the corrections needed to compensate for their effects on the atoms.
Improved time and frequency standards have many applications. For instance, ultraprecise clocks can be used to improve synchronization in precision navigation and positioning systems, telecommunications networks, and wireless and deep-space communications. Better frequency standards can be used to improve probes of magnetic and gravitational fields for security and medical applications, and to measure whether "fundamental constants" used in scientific research might be varying over time-a question that has enormous implications for understanding the origins and ultimate fate of the universe.
National Institute of Standards and Technology (NI
Improved time and frequency standards have many applications. For instance, ultraprecise clocks can be used to improve synchronization in precision navigation and positioning systems, telecommunications networks, and wireless and deep-space communications. Better frequency standards can be used to improve probes of magnetic and gravitational fields for security and medical applications, and to measure whether "fundamental constants" used in scientific research might be varying over time-a question that has enormous implications for understanding the origins and ultimate fate of the universe.
National Institute of Standards and Technology (NI
Atomic Clock Current Events and Atomic Clock News RSSNew JILA technique reveals hidden properties of ultracold atomic gases
Physicists at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder, have demonstrated a powerful new technique that reveals hidden properties of ultracold atomic gases.
New method to directly probe the quantum collisions of individual atoms
The first demonstration of a fundamentally new method for measuring a particular quantum property of individual atoms will be described in a research paper to be published in the 19 April 2007 edition of the journal Nature.
Atomic clock signals may be best shared by fiber-optics
Time and frequency information can be transferred between laboratories or to other users in several ways, often using the Global Positioning System (GPS). But today's best atomic clocks are so accurate—neither gaining nor losing one second in as long as 400 million years—that more stable methods are needed.
Biologists find biological clock for smell in mice
Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling center of mice brains and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours.
Physicists make atomic clock breakthrough
Andrei Derevianko, Kyle Beloy, and Ulyana Safronova sat down six months ago and began work on a calculation that will help the world keep better time. In competition with scientists at the University of New South Wales, the University team led by associate professor Derevianko conducted research that increased the accuracy of atomic clocks, and they did it without running a single experiment.
Mercury atomic clock keeps time with record accuracy
An experimental atomic clock based on a single mercury atom is now at least five times more precise than the national standard clock based on a "fountain" of cesium atoms.
New technologies enhance quantum cryptography
A team of Los Alamos National Laboratory scientists, in collaboration with researchers from the National Institute of Standards and Technology in Boulder, Colo., and Albion College, in Albion, Mich., have achieved quantum key distribution (QKD) at telecommunications industry wavelengths in a 50-kilometer (31 mile) optical fiber.
Tandem ions may lead the way to better atomic clocks
Physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have used the natural oscillations of two different types of charged atoms, or ions, confined together in a single trap, to produce the "ticks" that may power a future atomic clock.
Physicists lead the field in solving matter mystery of the Big Bang
A University of Sussex-led team of scientists is ahead in the race to solve one of the biggest mysteries of our physical world: why the Universe contains matter. With the help of a new £2.3 million grant, the team is working on a project to make one of the most sensitive measurements ever of sub-atomic particles. The results, expected within six years, could finally help to explain the creation of matter in the aftermath of the Big Bang. Physicist Dr Philip Harris, the leader of the Sussex group, says: "Although there are a couple of other teams in the world working in this same area, we're managing to stay ahead of them, and we are constantly striving to beat our own world record.
Galileo: contracts for the first satellites
The contracts for the first Galileo satellites were signed on Friday 11 July at ESTEC, the European Space Agency's research and technology centre. "Galileo is taking shape with every passing day. These first contracts are symbolic of Europe's collective resolve to develop the first civil global satellite navigation system", stated Claudio Mastracci, ESA Director of Application Programmes. The contracts are for two experimental satellites, forerunners of the system's in-orbit validation phase with one to be launched during the second semester of 2005, so as to secure the frequencies reserved for the Galileo system with the International Telecommunications Union; the signals have to be sent
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