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 ?
Three infrared lasers are focused on a cell filled with caesium vapour.
Contrary to expectation, it happened that the hydrogen maser, though potentially slightly superior to the caesium beam frequency standard, progressed only slowly (one of its uncertainties comes from the wall shift), and that caesium standards were so much improved that an almost perfect confidence was acquired in their reliability, within the most severe present needs of precision.
Although different elements have since been used in other clocks, the caesium clock has remained the standard of time and frequency.
In March 2013, TEPCO, the Japanese utility that operates the tsunami-damaged nuclear power plant, said it detected a record 740,000 becquerels per kilogram of radioactive caesium in a fish caught close to the plant, which was 7,400 times the government limit for safe human consumption.
Current detection methods can only localise contamination on a scale of metres to kilometres, and they do not specifically identify caesium. 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.
The 11 cows all showed high levels of radioactive caesium, ranging from 1,530 to 3,200 becquerels per kilogram, compared with the legal limit of 500 becquerels, the Tokyo statement said.
After being used inside a patient's body the caesium rod was thought to have been returned to a locked store.
The Bulgarian Atomic Agency yesterday admitted two cylinders of highly radioactive caesium 137 had been stolen from the Kremikovci smelting plant, just outside the capital Sofia.
Dounreay, , which is being decommissioned, is heavily contaminated with caesium and other heavy metals.
Caesium-137 accumulation or loss at each sampling point can be determined by subtracting the average caesium areal activity at the reference site from the areal activity at each sampling point following the method of Sutherland and de Jong (1990).