Ionizing radiation half-life

The radioisotope cobalt-60, with a half-life of 5.27 years (1925.3 days) through beta ((3) emission, decays to form the stable element nickel-60. It is used to test welds and metal casts for flaws, to irradiate food crops to prolong freshness, as a portable source of ionizing gamma (Y) radiation, for radiation research, and for a medical source of radiation to treat cancers and other diseases. 

The ESR spectra of polyisobutylene after irradiation with ultraviolet light (6) are different from those obtained after irradiation with ionizing radiation. The spectra consists mainly of two components one, a sharp quartet which has a half life of 1% hours at liquid nitrogen temperature, has been attributed to free methyl radicals (XI), in analogy with ultraviolet-irradiated polypropylene (51). The broad component is composed of many superimposed lines and was interpreted as caused by three different radicals, all stable at liquid nitrogen temperature. One of these radicals (XV) is the counterpart to the methyl radical (XI) while the others are the two radicals (XIII and XVI) which can both be formed by hydrogen abstraction. 

Americium-241 is widely used in smoke detectors. The radiation released by this element ionizes particles that are then detected by a charged-particle collector. The half-life of 24IAm is 432.2 years, and it decays by emitting alpha particles. How many alpha particles are emitted each second by a 5.00-g sample of 241Am ... 

Although has not been extensively used as yet, it promises to become one of the most useful of the isotopes. First made in 1940 by Ruben and Kamen, it has the advantage of a very long half-life and can be obtained having an appreciable specific radioactivity (3-6%). It emits electrons with essentially no 7-ray emission, and because of its weak radiation, must be measured with a thin mica-window counter or a suitable ionization chamber. 

Th is both chemotoxic and radiotoxic (Fisher 1988, Metivier 1988), whereas all other much shorter-lived thorium isotopes are dominated by their radiotoxicity due to the ionizing radiation emitted during their radioactive decay. This is the result of the inverse relationship between the specific radioactivity (Bq kg ) and the half-life of a radionuclide. 

Y has a rather short half-life, but its radiation is dangerous, since this radionuclide is produced continuously from °Sr accumulated in the skeleton, emitting radiation with a high ionization density [17]. 

How might we encounter ionizing radiation in chemistry labs Radioactive atoms are often inserted into molecules and then followed in a reaction scheme or a biological medium to determine the pathway and/or fate of the molecule. Some radioisotopes commonly used for this are (ti/2 = 12.3 yr) and (ti/2 = 14.3 days). The hazard level associated with these procedures is related to the quantity of the isotope, the decay products and their energy, and the radioactive half-life. 

The development of commercial plants using gamma radiation as the ionizing medium has centered around cobalt 60 because it is the cheapest source of gamma radiation power combined with a reasonable half-life of 5i years. In addition, it is virtually unaffected by radiation and can be used up to temperatures of nearly 1000°C. A low cost of production can sometimes be gained by using cobalt as a flux flattener, i.e., for controlling the reactivity of the core of a nuclear reactor. 

---