NIST comes up with chip-sized atomic clock
- By William Jackson
- Aug 30, 2004
Government researchers have demonstrated the works of an atomic clock the size of a grain of rice, opening the door for more precise timekeeping on portable and handheld devices.
Improved timekeeping could translate into more accurate navigation and improved security on military communications devices.
In its current form, the tiny clock is accurate to within one second every 300 years, about as good as quartz crystal clocks now used in portable devices. But scientists at the National Institute of Standards and Technology hope to improve that by several orders of magnitude.
'The real power of our technique is that we're able to run the clock on so little electrical power that it could be battery operated and that it's small enough to be easily incorporated into a cell phone,' said NIST physicist John Kitching, principal investigator. 'And nothing else like it even comes close to being mass-producible.'
The research has been supported by NIST and the Defense Advanced Research Projects Agency and was described in the Aug. 30 issue of Applied Physics Letters.
Precise timekeeping can improve network synchronization and channel selection to enhance security and anti-jamming. It also can improve the accuracy of Global Positioning System navigational systems.
Along with the U.S. Naval Observatory, NIST is one of the nation's official timekeepers and is responsible for defining and measuring the second. A second is defined by the frequency of the cesium-133 atom, which vibrates 9.2 billion times per second. The vibrations serve the same function as the pendulum of a clock.
NIST keeps time with its cesium atomic clock in Boulder, Colo. This type of clock is extremely accurate, but it also is large, expensive and uses lots of power. The new clock uses just 75 thousandths of a watt and could be assembled on semiconductor wafers using existing techniques.
William Jackson is a Maryland-based freelance writer.