BOULDER, Colo. — A new cesium fountain atomic clock at the National Institute of Standards and Technology (NIST) in Boulder is making time more accurate by fractions of a second.
It took a team of researchers three years to build the NIST-F4, and now that it is operational, it is one of only a few in the world.
"There are less than 30 ever built, and less than 20 in operation at the moment," said Vladislav Gerginov, a NIST physicist who worked on the clock.
The NIST-F4 measures a special resonance in the atom of cesium.
"Well, there is no ticking because the atoms are not ticking in the acoustic or mechanical sense. The internal structure oscillates at the given frequency. That happens at a very high frequency," said Gerginov. "So, even if you could somehow convert that into audio frequency, you wouldn't be able to hear it."
Inside the clock, cesium atoms are oscillating at the rate of around 9 billion cycles per second. The clock uses a technique called laser cooling to slow down the hot cesium atoms and then records the frequency that the atoms travel through a microwave chamber.
- Hear more from Gerginov in the video player below
Similar to how a pendulum clock swings to count seconds, the NIST-F4 recognizes the fast oscillations of the cesium atoms as a second, Gerginov explained.
"We use NIST-F4 to realize the unit of time, the second. We do that by measuring a special resonance in the atom of cesium that is an extremely narrow resonance, and the definition of the frequency of that resonance is tied to the length and the duration of the second," Gerginov said.
As complex as this clock is, it plays a major role in helping the world stay on time. According to NIST physicist Roger Brown, this new atomic clock is part of the "backbone to timekeeping."
"Everyone keeps their own wrist watch or their own local time, but all of those have a tendency to lose calibration and go out. And so, this is sort of like the central clock that all other clocks ultimately are calibrated against," Brown said.
Brown said the years put into the clock are necessary for its success.
"The fountain clock takes years to make and to perfect, but the essence of it is that it forms the definition of time as agreed upon internationally and its NIST best realization of that time," he shared.
Even though the NIST F-4 is described as precise and accurate, physicists like Brown are already working on the next new invention to help with the important role of timekeeping.
"I think that looking forward, though, there is a lot of new excitement to where next generation clocks could potentially measure things like gravitational fields on the earth and potentially make measurements much more quickly," Brown said.
