Gamma radiation accompanying

Am will grow with time in plutonium recycled for fabricating reactor fuel, as discussed in Chap. 8. The gamma radiation accompanying the decay of Am will contribute external radiation and may require personnel protection. 

Pure gamma emitters are rare, although gamma radiation accompanies most alpha and beta radiation. In radiology, one of the most commonly used gamma emitters is technetium (Tc). The unstable isotope of technetium is written as the metastable (symbol m)... 

This radiation release often accompanies the release of alpha or beta particles because of the high energy arrangement left in the nucleus after the release of alpha or beta particles. Gamma radiation has the greatest penetrating ability. Concrete, 6 inches thick, is needed to stop gamma radiation. 

The fifth type of radioactive emission, gamma radiation, does not result in a change in the properties of the atoms. As a result, they are usually omitted from nuclear equations. Gamma emissions often accompany other alpha or beta reactions—any decay that has an excess of energy that is released. For example, when a positron collides with an electron, two gamma rays are emitted, a phenomenon usually referred to as annihilation radiation. 

How is gamma radiation produced in a radioactive decay When a radioactive nucleus emits an alpha or beta particle, the nucleus is often left in an unstable, high-energy state. The relaxation of the nucleus to a more stable state is accompanied by the emission of gamma radiation. 

The positron has a short life and will quickly be annihilated in a reaction with an electron, producing y-photons of characteristic energy (0.51 MeV). In addition, the basic nuclear process itself is usually accompanied by the emission of gamma radiation. As in the case of negatron decay a complete energy balance reveals a discrepancy which can be accounted for if the emission of a further particle—the neutrino, v is postulated. Overall, positron emission can be summarized in a general equation... 

Prompt activation analysis (Erdtmann and Petri, 1986 Alfassi, 1990) uses the prompt radiation accompanying a nuclear reaction for determining elemental or isotopic concentrations. The variety of prompt methods is large because a sample can be irradiated with various particles - neutrons, charged particles or gamma-rays. Prompt activation analysis permits the determination of several elements - about 17 elements in environmental matrices (Germani et al., 1980) - but most analysis are used for the determination of light elements (H, He, Li, B, C, N, Si, S, Cl) as well of Cd and Gd. 

The long half-life of iodine-129, 15.7 million years, means that it remains in the environment. However, iodine-131 s short half-life of 8 days means that it will decay away completely in the environment in a matter of months. Both decay with the emission of a beta particle, accompanied by weak gamma radiation. 

All uranium isotopes are radioactive. The three namral uranium isotopes found in the environment, U-234, U-235, and U-238, undergo radioactive decay by emission of an alpha particle accompanied by weak gamma radiation. The dominant isotope, U-238, forms a long series of decay products that includes the key radionuclides radium-226, and radon-222. The decay process continues until a stable, non-radioactive decay product is formed (see uranium decay series). The release of radiation during the decay process raises health concerns. 

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