Radioactive Decay and Interaction of Radiation with Matter

Radioactive Decay and Interaction of Radiation with Matter... 

There are three significant possible effects when radiation interacts with matter (5,6). First, the radiation can interact with the nucleus and induce radioactivity as in the case of neutrons. Second, displacement of atoms can occur. This has happened in a number of uranium- and thorium-containing minerals over geological periods. The outstanding example is zircon, which can contain over 10% Th and 2% U. The internal bombardment from these materials and their decay products over geological periods produces low or metamict zircon, where the disorder gives an amorphous state having a low density. 

A comprehensive description of the nature of radioactivity and its interaction with matter is beyond the scope of this chapter, and such information can easily be found elsewhere (Shleien et al., 1998 CPEP, 2003 Tykva, 2004). Here we give only a brief sketch of the basic principles. Radioactivity is a natural phenomenon, discovered in 1896 by Henri Becquerel. The nuclei of some atoms are unstable and decay spontaneously, emitting ionizing radiation to attain a more energetically favorable state. Radioisotopes are characterized by the nature of the... 

L Annunziata, M.F. 2003. Nuclear radiation, its interaction with matter and radioisotope decay. In L Annunziata, M.F. (Ed.). Handbook of Radioactivity Analysis, 2nd edn. Oxford Elsevier Ltd., Oxford, U.K., pp. 1-121. 

Certain interactions with matter of the radiation accompanying the decay of unstable nuclides (a- and /9-particles, y rays) are the basis for the detection and measurement of radioactivity These include photochemical processes, by which a radioactive sample placed in close contact with photographic emulsion causes blackening of the latter upon development (autoradiography) gas ionisation and the deriving production of current pulses that can be analysed and measured by suitable devices excitation of orbital electrons of special molecules, either in a crystalline form or in solution, with subsequent emission of light pulses to be converted into electric current by a photoelectric detector (scintillation)... 

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