Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIST launches a new US time standard: NIST-F2 atomic clock

04.04.2014

The U.S. Department of Commerce's National Institute of Standards and Technology (NIST) has officially launched a new atomic clock, called NIST-F2, to serve as a new U.S. civilian time and frequency standard, along with the current NIST-F1 standard.

NIST-F2 would neither gain nor lose one second in about 300 million years, making it about three times as accurate as NIST-F1, which has served as the standard since 1999. Both clocks use a "fountain" of cesium atoms to determine the exact length of a second.


National Institute of Standards and Technology physicists Steve Jefferts (foreground) and Tom Heavner with the NIST-F2 'cesium fountain' atomic clock, a new civilian time standard for the United States.

Credit: National Institute of Standards and Technology

NIST scientists recently reported the first official performance data for NIST-F2,* which has been under development for a decade, to the International Bureau of Weights and Measures (BIPM), located near Paris, France. That agency collates data from atomic clocks around the world to produce Coordinated Universal Time (UTC), the international standard of time. According to BIPM data, NIST-F2 is now the world's most accurate time standard.**

NIST-F2 is the latest in a series of cesium-based atomic clocks developed by NIST since the 1950s. In its role as the U.S. measurement authority, NIST strives to advance atomic timekeeping, which is part of the basic infrastructure of modern society. Many everyday technologies, such as cellular telephones, Global Positioning System (GPS) satellite receivers, and the electric power grid, rely on the high accuracy of atomic clocks. Historically, improved timekeeping has consistently led to technology improvements and innovation.

"If we've learned anything in the last 60 years of building atomic clocks, we've learned that every time we build a better clock, somebody comes up with a use for it that you couldn't have foreseen," says NIST physicist Steven Jefferts, lead designer of NIST-F2.

For now, NIST plans to simultaneously operate both NIST-F1 and NIST-F2. Long-term comparisons of the two clocks will help NIST scientists continue to improve both clocks as they serve as U.S. standards for civilian time. The U.S. Naval Observatory maintains military time standards.

Both NIST-F1 and NIST-F2 measure the frequency of a particular transition in the cesium atom—which is 9,192,631,770 vibrations per second, and is used to define the second, the international (SI) unit of time. The key operational difference is that F1 operates near room temperature (about 27 ºC or 80 ºF) whereas the atoms in F2 are shielded within a much colder environment (at minus 193 ºC, or minus 316 ºF). This cooling dramatically lowers the background radiation and thus reduces some of the very small measurement errors that must be corrected in NIST-F1. (See backgrounder on clock operation and accompanying animation of NIST-F2 at http://www.nist.gov/pml/div688/how-nist-f2-works.cfm)

Primary standards such as NIST-F1 and NIST-F2 are operated for periods of a few weeks several times each year to calibrate NIST timescales, collections of stable commercial clocks such as hydrogen masers used to keep time and establish the official time of day. NIST clocks also contribute to UTC. Technically, both F1 and F2 are frequency standards, meaning they are used to measure the size of the SI second and calibrate the "ticks" of other clocks. (Time and frequency are inversely related.)

NIST provides a broad range of timing and synchronization measurement services to meet a wide variety of customer needs. NIST official time is used to time-stamp hundreds of billions of dollars in U.S. financial transactions each working day, for example. NIST time is also disseminated to industry and the public through the Internet Time Service, which as of early 2014 received about 8 billion automated requests per day to synchronize clocks in computers and network devices; and NIST radio broadcasts, which update an estimated 50 million watches and other clocks daily.

At the request of the Italian standards organization, NIST fabricated many duplicate components for a second version of NIST-F2, known as IT-CsF2 to be operated by Istituto Nazionale di Ricerca Metrologica (INRIM), NIST's counterpart in Turin, Italy. Two co-authors from Italy contributed to the new report on NIST-F2.

The cesium clock era officially dates back to 1967, when the second was defined based on vibrations of the cesium atom. Cesium clocks have improved substantially since that time and are likely to improve a bit more. But clocks that operate at microwave frequencies such as those based on cesium or other atoms are likely approaching their ultimate performance limits because of the relatively low frequencies of microwaves. In the future, better performance will likely be achieved with clocks based on atoms that switch energy levels at much higher frequencies in or near the visible part of the electromagnetic spectrum. These optical atomic clocks divide time into smaller units and could lead to time standards more than 100 times more accurate than today's cesium standards. Higher frequency is one of a variety of factors that enables improved precision and accuracy.

###

* T.P. Heavner, E.A. Donley, F. Levi, G. Costanzo, T.E. Parker, J.H. Shirley, N. Ashby, S.E. Barlow and S.R. Jefferts. First Accuracy Evaluation of NIST-F2. Metrologia. Forthcoming. See http://iopscience.iop.org/0026-1394/page/Forthcoming%20articles.

** These data are reported monthly in BIPM's Circular T, available online at http://www.bipm.org/jsp/en/TimeFtp.jsp?TypePub=publication#nohref. NIST-F2 is scheduled to be listed for the first time in the March 2014 edition. The value of interest is Type B (systematic) uncertainty.

Laura Ost | EurekAlert!

Further reports about: NIST NIST-F1 Technology accuracy cesium clock frequencies measurement vibrations

More articles from Physics and Astronomy:

nachricht Hubble observes one-of-a-kind star nicknamed 'Nasty'
22.05.2015 | NASA/Goddard Space Flight Center

nachricht Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents
22.05.2015 | Universität Basel

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

Im Focus: Into the ice – RV Polarstern opens the arctic season by setting course for Spitsbergen

On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.

RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...

Im Focus: Gel filled with nanosponges cleans up MRSA infections

Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.

To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Mesoporous Particles for the Development of Drug Delivery System Safe to Human Bodies

22.05.2015 | Materials Sciences

Computing at the Speed of Light

22.05.2015 | Information Technology

Development of Gold Nanoparticles That Control Osteogenic Differentiation of Stem Cells

22.05.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>