Cesium-137 is a radioactive isotope (radioisotope) of the chemical element cesium (Cs), whose atomic number (Z), that is, the number of protons in the atomic nucleus, is 55, and the number of neutrons is 82. Thus, the name "cesium-137" comes from the your mass number (A), which corresponds to the sum of the atomic number with the neutrons (55 + 82 = 137). Thus, its representation is given by:55137Cs.
Cs-137 was discovered using a technique called spectroscopy by scientists Robert W. AND. Bunsen (1811-1899) and Gustav R. Kirchhoff (1824-1887), who were respectively professors of chemistry and physics at the German University of Heildelberg.
This radioisotope emits radiation from its core. As shown below, it disintegrates, releasing, for example, beta radiation (-10β), with the consequent formation of another even more harmful radioactive element, barium-137:
55137Cs → -10β + 56137Ba
Cesium-137 is quite dangerous for humans because it emits ionizing particles and electromagnetic radiation capable of passing through various materials, including the skin and tissues of the human body, interacting with the body's molecules and generating effects devastating. This interaction occurs because, as with all radioactive isotopes, Cs-137 emits radiation with enough energy to remove electrons from atoms and give rise to cations (positively charged particles), which are highly reactive and, in turn, can cause changes in reactions that occur in living tissue cells, altering the DNA and possibly causing the appearance of cells carcinogens.
The beta particle released by cesium-137 can penetrate up to 2 cm when it hits the human body and cause serious damage. Along with beta particles, gamma radiations are also released (00γ), which have an even higher penetration power and can completely penetrate the human body, causing irreparable damage. Barium-137 from cesium-137 also releases gamma radiation.
As an element of the alkali metal family (family 1 in the Periodic Table), Cesium is similar to potassium (K) (which also belongs to this family) and is able to replace it in tissues alive.
An example of how harmful this radioisotope can be was the accident that occurred in September 1987, in Goiânia - Goiás. Briefly, two garbage collectors found a capsule that contained cesium-137 (actually, had about 19 g of cesium chloride (CsC?) which was among the rubble of a hospital disabled. The scavengers took the capsule and sold it to a junkyard. The capsule was eventually violated and released the radioactive material, which caught the attention of many due to the luminescence of cesium, which is a powder that glows in the dark, in a bluish hue. The name of this element even has its origins in Latin“caesius", which means blue sky. The result was the death of four people, the contamination of more than 200 and the generation of more than 7 tons of nuclear waste.
Cesium-137 contamination can be prevented by insulating it with thick concrete walls.
Cesium-137, however, has several beneficial uses, such as in industries, in food preservation and, mainly, in medicine. In the radiotherapy device, its radioactive beam is used to attack cancer cells, and the lead in the capsule prevents this radiation from passing through and contaminating the surrounding materials. Today, cobalt-60 is used in place of cesium-137.
Cs-137 is also absorbed by water and soil, with a half-life (time required for half of its radioactive atoms to disintegrate) of approximately 30 years.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/quimica/o-que-e-cesio-137.htm