NIST-F1 is a caesium fountain atomic clock that serves as the United States' primary time and frequency standard. As of the summer of 2005, it is so accurate that it will neither gain nor lose one second in more than 80 million years. The clock took less than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of the National Institute of Standards and Technology (NIST) physics lab in Boulder, Colorado.
The clock replaces NIST-7, a caesium beam atomic clock used from 1993 to 1999. NIST-F1 is approximately 10 times more accurate than NIST-7. NIST-F1 will eventually be replaced by the NIST-F2.
Similar atomic fountain clocks, with comparable accuracy, are operated by other time and frequency laboratories, such as the Paris Observatory and the Physikalisch-Technische Bundesanstalt in Germany.
External links and references
- NIST-F1 Cesium Fountain Atomic Clock: The Primary Time and Frequency Standard for the United States (National Institute of Standards and Technology)
- U.S. Atomic Time
- S R Jefferts, J Shirley, T E Parker, T P Heavner, D M Meekhof, C Nelson, F Levi, G Costanzo, A De Marchi, R Drullinger, L Hollberg, W D Lee and F L Walls (2002). "Accuracy evaluation of NIST F-1". Metrologia 39: 321–336. doi:. http://www.boulder.nist.gov/timefreq/general/pdf/1823.pdf.
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