U.S. marches to tick of new clock

NIST physicists work with the NIST-F2 atomic clock.


Guest post by Andrew Grant

The atomic clock NIST-F2 has launched as the country’s official civilian time and frequency standard, researchers from the National Institute of Standards and Technology in Boulder, Colo., announced at a press conference April 3. Now the world’s best standard-setting clock, NIST-F2 has about three times the accuracy of NIST-F1, which has helped synchronize U.S. telecommunications networks and power grids since 1999. NIST-F2 is accurate to 10 trillionths of a second per day, or 1 second per 300 million years.

Both atomic clocks measure the laser frequency required to excite cesium atoms, which the international community uses to define the second. Researchers squeezed more accuracy out of NIST-F2 by lowering its operating temperature from 27 degrees Celsius to -193, limiting complications caused by the walls of the room reradiating heat.

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