What is the decay constant for Cs-137?
Cs decays with a half-life of (30.05 ± 0.08) years [4] to either the 137Ba ground state, with emission of a β particle (Q = 1176 keV, 5.3%), or to 137mBa (Q = 514 keV, 94.7%) which rapidly (t1/2 = 2.552 min) decays to the 137Ba ground state with emission of a 661.7 keV γ photon.
What type of decay does cesium-137 undergo?
beta particles
Cesium-137 decays in the environment by emitting beta particles. As noted above, cesium-137 decays to a short lived decay product, barium-137m. The latter isotope emits gamma radiation of moderate energy, which further decays to a stable form of barium.
When the nuclide Cesium-137 decays to barium-137 what kind of decay does cesium 137 undergo?
Cesium-137 undergoes β- decay, decaying into barium-137. Measurements of the emitted electrons show that the maximum electron energy is 1.176 MeV.
What does it mean to say Caesium 137 has a half-life of 30 years?
Cesium has a half-life of 30 years, which means that the 0.2 Ci of Cs-137 will decay down to one-tenth of a curie in about 30 years. Cs-137 is a cesium isotope that emits beta and gamma radiation.
What does cesium-137 look like?
Small amounts of Cs-137 are incorporated into Lucite disks, rods, and seeds. If the lead containers of Cs-137 are opened, the substance inside looks like a white powder and may glow. Cs-137 from nuclear accidents or atomic bomb explosions cannot be seen and will be present in dust and debris from fallout.
Does cesium-137 occur naturally?
Despite its prevalence in spent nuclear fuel and nuclear waste, cesium-137 is actually extremely rare. Its half-life is too short for it to persist from natural fission sources, and on earth it is a synthetic isotope only.
Is Cesium-137 stable or unstable?
Cesium-137 has a radioactive half-life of about 30 years and decays by beta decay either to stable barium-137 or a meta-stable form of barium (barium-137m).
Why is barium-137 Safe?
This Cs-137/Ba-137m Isotope Generator is used to demonstrate the properties of radioactive decay. Approximately 30 minutes after elution, the residual activity of the Ba-137m sample has decayed to less than one thousandth of its initial activity, making it safe for disposal.
When the isotope cesium-137 decays by beta emission What is the atomic number of the element produced?
Cesium-137 is a radioactive element with a half-life of thirty years. Its decay results in the formation of Ba-137 with a very short half-life. Both elements have the same atomic mass but cesium has an atomic number of 55 and barium has an atomic number of 56.
Who discovered cesium-137?
In 1860, R. W. Bunsen and G. R. Kirchoff discovered the element (the first to be discovered by the use of the spectroscope) and named it for the two bright blue lines characteristic of its spectrum. It was first isolated by Carl Sefferburg in 1881 by electrolysis of its salts.
How long would it take cesium-137 to become safe to dispose of?
approximately 180 years
Cesium-137 remains radioactive for approximately 180 years. Cesium is the most electropositive and most alkaline element, and thus, it loses its single valence electron and forms electrovalent bonds more easily than all other elements and it does so with nearly all the inorganic and organic anions.
Is Cesium-137 naturally occurring?
How does Cs-137 disintegrate to the ground state?
LNE – LNHB/CEA – Table de Radionucl´eides. 137 55 Cs 82. 1 Decay Scheme. Cs-137 disintegrates by beta minus emission to the ground state of Ba-137 (5,6 %) and via the 661 keV isomeric level of Ba-137 (94,4 %) which has a half-life of 2,55 min.
What does red mean in the F 18 decay scheme?
F 18 Decay Scheme The colour red indicates that the nucleus decays by electron capture / positron emission.
What is the half life of Cs 137?
Cs-137 disintegrates by beta minus emission to the ground state of Ba-137 (5,6 %) and via the 661 keV isomeric level of Ba-137 (94,4 %) which has a half-life of 2,55 min.
What is the gamma ray activity of caesium 137?
A total of 85.1% of Cs-137 decays lead to gamma ray emission in this way. One gram of caesium-137 has an activity of 3.215 tera becquerel (TBq). The main photon peak of Ba-137m is 662 keV.