New Atomic Fountain Clock Joins Elite Group That Keeps the World on Time

NIST-F4, a new atomic clock at NIST in Boulder, Colorado, is among the world's most accurate. It measures the frequency of cesium atoms, the international standard for defining a second. The clock uses a fountain design, achieving exceptional accuracy. If operating since the dinosaur age, it would be less than a second off today. NIST submitted NIST-F4 to the BIPM for acceptance as a primary frequency standard. Its inclusion strengthens global timekeeping stability and security. NIST-F4 helps maintain official U.S. time. Official U.S. time, distributed online and via radio, is crucial for various systems. These systems include telecommunications, transportation, finance, and data centers. The clock's accuracy improves the reliability of these critical services.