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Caesium-137 (137 55 Cs), cesium-137 (US), [7] 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 Scheme of Caesium-137. Based on a public domain image by Kieran Maher (see original image) Date: 31 August 2006: Source: Own work: Author: Dirk Hünniger: Other versions: Derivative works of this file: Caesium-137 Decay Scheme-de-2.svg
It is also not produced by nuclear weapons because 135 Cs is created by beta decay of original fission products only long after the nuclear explosion is over. 136 Cs also captures neutrons with a cross section of 13.00 barns, becoming medium-lived radioactive 137 Cs. Caesium-136 undergoes beta decay (β−), producing 136 Ba directly.
The accompanying decay scheme diagram shows the beta decay of caesium-137. 137 Cs is noted for a characteristic gamma peak at 661 keV, but this is actually emitted by the daughter radionuclide 137m Ba. The diagram shows the type and energy of the emitted radiation, its relative abundance, and the daughter nuclides after decay.
As caesium 133, 135, and 137 are formed by the beta particle decay of the corresponding xenon isotopes, this causes the caesium to become physically separated from the bulk of the uranium oxide fuel. Because 135 Xe is a potent nuclear poison with the largest cross section for thermal neutron absorption, the buildup of 135 Xe in the fuel inside ...
Decay modes in parentheses are still not observed through experiment but are, by their energy, predicted to occur. Numbers in brackets indicate probability of that decay mode occurring in %, tr indicate <0.1%. Spontaneous fission is not shown as a theoretical decay mode for stable nuclides where other modes are possible (see these nuclides).
A mining company dropped a tiny capsule of caesium-137 somewhere along an 870-mile stretch of Western Australia’s Great Northern Highway. The plan is to find it before someone gets hurt, Liam ...
Date/Time Thumbnail Dimensions User Comment; current: 13:42, 28 August 2011: 624 × 345 (14 KB): Kalin.KOZHUHAROV: added color and made consistent use of styles: 10:22, 26 March 2011