Agent Name
Cesium, radioactive
Major Category
Physical/Radiation
Synonyms
Caesium; The most important radionuclides are Cesium-134 (13967-70-9) and Cesium-137 (10045-97-3); For the stable isotope, see "Cesium" and "Cesium hydroxide."
Description
Silver metal with a melting point of 28.5 degrees C. Reacts explosively with water to form cesium hydroxide; [Merck Index] The mineral, pollucite, is 13% stable cesium oxide;
Sources/Uses
Naturally occurring is Cs-133 (7440-46-2). "Radioactive cesium-137 is produced when uranium and plutonium absorb neutrons and undergo fission." [ATSDR] Of the 11 major radionuclides, only three have long enough half-lives to persist in the environment: Cs-134, Cs-135, and Cs-137. The decay product of Cs-137 is Ba-137m with a T1/2 of 2.6 minutes. Ba-137m emits a gamma ray with an energy of 0.6 MeV, and this is what makes Cs-137 an external radiation hazard. Cs-137 is used in cancer radiation therapy. [Argonne]
Comments
Most Important Radionuclide: Cs-137
Source: Fission of uranium and plutonium;
Half-Life: 30 years
Effective Half-Life: 70 days
Specific Activity: 88 Ci/g
Decay Mode: Beta
GI Absorption: "essentially all"
Lung Clearance Half-Time: Days (all compounds)
Critical Organ: Total body;
Internal Toxicity: High
Annual Limit on Intake: 0.1 mCi
Tenth-Value Layer: 18.9 mm Pb
Gamma Ray Constant: 3.5 R/h @1 cm per mCi
Radiation Energy (MeV): Beta 0.514 (95%); Ba-137m Daughter
Radiation Accidents: Goiania, Brazil accident in 1987 with 50 people contaminated and 4 deaths from a Cs-137 source (1375 Ci) taken from an abandoned teletherapy machine; 6 other accidents and 25 reports of "Meltings of Radioactive Materials";
[See Glossary for references.] See "Radiation, ionizing."
Vapor Pressure
4.24E-09 mm Hg
Other Information
No other related information on this agent was found.