This article highlights the efforts of physicist Vladislav Gerginov at the National Institute of Standards and Technology (NIST) to restore a cesium fountain clock, known as NIST-F4, to full operation. Cesium fountain clocks are among the most accurate timekeeping devices in the world and serve as primary standards for defining the second, the official unit of time. These clocks are essential for maintaining global time synchronization, which supports systems like GPS, telecommunications, and financial networks. After a move to a new building in 2016, NIST’s previous fountain clock, NIST-F1, was no longer operational, leaving the U.S. reliant on other countries for precise timekeeping.
Gerginov led a complex restoration effort, including rebuilding the microwave cavity at the heart of the clock and fine-tuning various components to achieve extreme precision. The team faced numerous challenges, such as environmental disturbances and unexpected noise in measurements, which required months of troubleshooting. In early 2024, NIST-F4 achieved an accuracy of 2.2 parts in 10 quadrillion, making it one of the most precise fountain clocks globally. This restoration ensures that NIST can once again contribute to international timekeeping efforts and maintain the U.S.’s role in defining the official second.
Source: https://www.nist.gov/atomic-clocks/bringing-atomic-clock-back-life
Keywords: cesium fountain clock, atomic clock, frequency standard
