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The United States uses two primary atomic clocks for official measurements:  the NIST-F1 in Boulder, Colo. from the National Instutute of Standards and Techology, and the U.S. Naval Observatory  Master Clock in Washington, D.C.


Atomic clock technology ticks into new territory

by Brian Warmoth
May 20, 2011


Average nine-to-five urbanites may not care whether their alarm clocks lose a second every few billion years. When it comes to location-based technologies and outer space exploration, however, every billionth of a second counts.

A team of American and Russian physicists announced last week that they have improved temperature computation methods for atomic clocks to an unprecedented degree. Now, their findings could mean a long tick forward for other technologies such as GPS and broadband communication.

“The real target is to attain the highest accuracy that we currently think is possible for the current generation of atomic clocks," said Charles W. Clark, one of the project’s contributors and a physicist at the National Institute of Standards and Technology in Gaithersberg, Md.

Atomic clocks rely on precise measurements on extremely small levels, calculating an atom’s resonating frequency to keep track of time. Clark and his colleagues looked for a way to offset distortions caused by a process called blackbody radiation during those calculations.

Blackbody radiation causes electron clouds to swell as the result of environmental temperatures. The energy increase that occurs can lead to subtle measurement offsets over billions of years.

The new calculations can help future researches to account for a blackbody radiation shift and vastly improve the quality of their measurements, according to Marianna Safronova, a physicist at the University of Delaware in Newark and the lead author on the paper presented at the 2011 Conference of Lasers and Electro-Optics in Baltimore, Md.

"This is actually a revolutionary development,” Clark said. He hopes that the computing advances made by his team will enable the scientific community to account for blackbody radiation and in doing so study the world’s most accurate atomic clock in Boulder, Colo., which belongs to the NIST, and make improvements in future models.

Previously, atomic clock technology has been able to measure electron clouds’ frequencies, resulting in one second being lost about every 3.7 billion years monitoring aluminum ions. With the new computation strategies formulated by Safranova and Clark’s team, however, they believe that science can now produce a clock that loses only 1 second about every 80 billion years

Their accomplishments should in turn improve the accuracy of other devices and technologies that use atomic clocks as reference points. Farmers with GPS-guided machinery, for instance, would be able to target rows and individual plants more acutely.

“The reason you able pinpoint your location to within a few meters is because of atomic clocks,” NIST spokesman Ben Stein explained.

Additionally, the ability to measure temperature differences more accurately on an atomic scale has applications in the mining industry.

"Another application is in the measurement of the Earth's gravitational field,” Clark said. Their advancements could aid velocity change measurement, inertial measurement and mineral exploration.

"If you have a deposit of iron ore, its density tends to be different from that of the surrounding environment," he said.

With temperature readings now extending into the eighteenth decimal place and only one second being lost every 80 million years, higher quality measurements in many fields could be on the horizon. However, only someone living longer than the known universe would need to worry about noticeable improvements to their alarm clock.