The physicists evaluated the recently upgraded caesium fountain clock with physical measurements at NPL and mathematical models developed at Penn State.
Washington, Aug 27 (ANI): A caesium fountain clock that keeps the United Kingdom's atomic time is now the most accurate long-term timekeeper in the world.
Until they reach this accuracy, caesium
fountain clocks, however, need a certain measurement time.
Researchers in Japan, led by Katsuhiko Ariga at the National Institute for Materials Science, have now developed a way to detect caesium
contamination on a scale of millimetres.
Under Japanese Food Sanitation Law, 5,000 becquerel per kg (Bq/kg) of caesium
is considered the safe limit in soil (caesium
-137 makes up about half of total radioactive caesium