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Caesium-137 (137 55 Cs), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons. Trace quantities also originate from spontaneous fission of uranium-238. It is ...
Decay of caesium-137. The radioactive 135 Cs has a very long half-life of about 2.3 million years, the longest of all radioactive isotopes of caesium. 137 Cs and 134 Cs have half-lives of 30 and two years, respectively. 137 Cs decomposes to a short-lived 137m Ba by beta decay, and then to nonradioactive barium, while 134 Cs transforms into 134 ...
Caesium ( 55 Cs) has 41 known isotopes, the atomic masses of these isotopes range from 112 to 152. Only one isotope, 133 Cs, is stable. The longest-lived radioisotopes are 135 Cs with a half-life of 1.33 million years, 137. with a half-life of 30.1671 years and 134 Cs with a half-life of 2.0652 years. All other isotopes have half-lives less ...
List of radioactive nuclides by half-life. This is a list of radioactive nuclides (sometimes also called isotopes ), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds. [1]
Once it has been calibrated and as long as the source detector alignment remains constant, it is possible to calculate the density of the liquid in the pipe. One factor is the half-life of the radioactive source (30 years for 137 Cs), which means that the system needs to be recalibrated at regular intervals. Modern systems incorporate ...
Caesium-137 is one such radionuclide. It has a half-life of 30 years, and decays by beta decay without gamma ray emission to a metastable state of barium-137 (137m Ba). Barium-137m has a half-life of a 2.6 minutes and is responsible for all of the gamma ray emission in this decay sequence. The ground state of barium-137 is stable.
Caesium-137, with a half-life of 30 years, is the main medium-lived fission product, along with Sr-90. Cs-137 is the primary source of penetrating gamma radiation from spent fuel from 10 years to about 300 years after discharge.
Naturally occurring cerium ( 58 Ce) is composed of 4 stable isotopes: 136 Ce, 138 Ce, 140 Ce, and 142 Ce, with 140 Ce being the most abundant (88.48% natural abundance) and the only one theoretically stable; 136 Ce, 138 Ce, and 142 Ce are predicted to undergo double beta decay but this process has never been observed.