INTEGRAL EQUATIONS GOVERNING RADIATION EFFECTS. (NOTES ON ATOMIC COLLISIONS, III)

A theoretica study is made of damage effects by particle radiations in mater, and their dependence on energy, mass,, and charge number of an incoming particle, as well as on the composition of the medium. Typical examples of damage effects are the number of ion pairs formed in a gas, or the number of vacancies created in a crystal. The study is petition between energy transfer to atomic electrons and to translatory motion on of an atoms as a whole. For these purposes, common integril equations are formulated and studied. The study treats primarily average effects resulting from an atomic particle with given energy, but also their average fluctuation and probability distribution. As an important example, the division of the total energy dissipation, E, into energy given to recoiling atoms, nu , and energy given to electrons, E- nu , is studied. Several radiation effects are accounted for from knowledge about E and nu . The primary quantities in a study of radiation effects are the cross sections for all relevant collision processes. of cross sections are used, desimple approximations are introduced; analytical and numerical estimates are made of solutions to the integral equations. For many purposes, nuclear collisions andmore » electronic collisions may be treated as if they were unconnected events, although this is not quite correct, especially at low energies. Considerable simplification is obtained by a suitable scaling of energy. A key to a common experimental and theoretical study is provided by an incoming particle identical with the atoms of the substance. Only few experiments can at present be compared quantitatively with theory. (auth)« less