Gamma Sources Commonly Used

ALPHA, Table Cl Alpha Sources BETA, AND GAMMA SOURCES COMMONLY USED ... 

The most commonly used sources of radiation are the 60 Co gamma source for continuous irradiation and pulsed high-energy (>1 MeV) electron beams for fast kinetic studies. Detailed descriptions of several such sources and accelerators are given in numerous books, as are the various methods used by radiation chemists for dosimetry, sample preparation and irradiation, and common product analysis. Several new developments in the analytical procedures, both in the determination of final products and in the direct observation of transient species, will be discussed below. 

Certain radioactive decay processes can be used to provide a source of gamma radiation for radiolysis. One particularly useful isotope is Co, which is produced by thermal neutron bombardment of Co. Co has a half-life of 5.27 yr and emits gamma radiation with an average energy of 1.2 MeV. Another commonly used gamma source is Cs (half-life 30.17 yr, 0.66 MeV). 

In many applications, ionizing radiation is used to improve specific properties of polymer materials, to steriUze medical devices, preserve food and to treat waste materials. Electrons and X-rays from particle accelerators or the gamma radiation from cobalt-60 are commonly used. In both cases, the transfer of the radiation energy to absorbing materials is achieved by means of secondary electrons, and the physical and biological effects observed for both t)rpes of radiation sources are very similar. 

Gamma-gamma-tools in the Compton energy region (0.5-5 MeV) measure a material response controlled by the number of orbiting electrons per unit volume. Commonly used nuclear sources are caesium (0.66 MeV) and cobalt (1.17 and 1.33 MeV). 

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