Related topics: fukushima

A quantum simulation of Unruh radiation

Researchers at the University of Chicago (UChicago) have recently reported an experimental observation of a matter field with thermal fluctuations that is in accordance with Unruh's radiation predictions. Their paper, published ...

Researchers modify magnetic behavior of exotic materials

People are not the only ones to be occasionally frustrated. Some crystals also show frustrations. They do so whenever their elementary magnets, the magnetic spins, cannot align properly. Cesium copper chloride (Cs2CuCl4) ...

How heavy elements come about in the universe

Heavy elements are produced during stellar explosion or on the surfaces of neutron stars through the capture of hydrogen nuclei (protons). This occurs at extremely high temperatures, but at relatively low energies. An international ...

Radioactivity lingers from 1946-1958 nuclear bomb tests

Scientists have found lingering radioactivity in the lagoons of remote Marshall Island atolls in the Pacific Ocean where the United States conducted 66 nuclear weapons tests in the 1940s and 1950s.

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Caesium

Caesium or cesium ( /ˈsiːziəm/ see-zee-əm) is the chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at (or near) room temperature. Caesium is an alkali metal and has physical and chemical properties similar to those of rubidium and potassium. The metal is extremely reactive and pyrophoric, reacting with water even at −116 °C (−177 °F). It is the least electronegative element that has stable isotopes, of which it has only one, caesium-133. Caesium is mined mostly from pollucite, while the radioisotopes, especially caesium-137, a fission product, are extracted from waste produced by nuclear reactors.

Two German chemists, Robert Bunsen and Gustav Kirchhoff, discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium have been as a "getter" in vacuum tubes and in photoelectric cells. In 1967, a specific frequency from the emission spectrum of caesium-133 was chosen to be used in the definition of the second by the International System of Units. Since then, caesium has been widely used in atomic clocks.

Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids. It has a range of applications in the production of electricity, in electronics, and in chemistry. The radioactive isotope caesium-137 has a half-life of about 30 years and is used in medical applications, industrial gauges, and hydrology. Although the element is only mildly toxic, it is a hazardous material as a metal and its radioisotopes present a high health risk in case of radiation leaks.

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