caesium


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Related to caesium: caesium 137

caesium

(US), cesium
a ductile silvery-white element of the alkali metal group that is the most electropositive metal. It occurs in pollucite and lepidolite and is used in photocells. The radioisotope caesium-137, with a half-life of 30.2 years, is used in radiotherapy. Symbol: Cs; atomic no.: 55; atomic wt.: 132.90543; valency: 1; relative density: 1.873; melting pt.: 28.39±0.01°C; boiling pt.: 671°C
References in periodicals archive ?
Although different elements have since been used in other clocks, the caesium clock has remained the standard of time and frequency.
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.
Vast areas were contaminated with caesium 134 and caesium 137 following the accident at the Chernobyl nuclear power station on April 26, 1986 (1).
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.