NIST-F1

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NIST-F1 is a cesium 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 60 million years. The clock took less than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of NIST's Boulder, Colorado physics lab.

The clock replaces NIST-7, a cesium beam atomic clock used from 1993 to 1999. NIST-F1 is approximately 10 times more accurate than NIST-7.

[edit] 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