NIST-F1

NIST-F1, source of the official time of the United States

NIST-F1 is a cesium fountain clock, a type of atomic clock, in the National Institute of Standards and Technology (NIST) in Boulder, Colorado, and serves as the United States' primary time and frequency standard. The clock took less than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of the Time and Frequency Division of NIST's Physical Measurement Laboratory.[1]

The clock replaced NIST-7, a cesium beam atomic clock used from 1993 to 1999. NIST-F1 is ten times more accurate than NIST-7. It has been succeeded by a new standard, NIST-F2, announced in April 2014. The NIST-F2 standard aims to be about three times more accurate than the NIST-F1 standard, and there are plans to operate it simultaneously with the NIST-F1 clock.[2] The most recent contribution of NIST-F1 to BIPM TAI was in March 2016.[3]

  1. ^ "NIST-F1 Cesium Fountain Atomic Clock: The Primary Time and Frequency Standard for the United States". NIST. August 26, 2009. Retrieved 2 May 2011.
  2. ^ Ost, Laura (April 3, 2014). "NIST Launches a New U.S. Time Standard: NIST-F2 Atomic Clock". Nist. Retrieved 2 January 2015.
  3. ^ "BIPM - Time Department FTP server". www.bipm.org. Retrieved 2019-04-18.