[Possibilities to improve the adaptation quality of calculated material substitutes (author's transl)]

In calculating the composition of material substitutes by a system of simultaneous equations it is possible, by using a so called quality index, to find out of the set of solutions which generally exists that solution which possesses the best adaptation quality. Further improvement is often possible by describing coherent scattering and photoelectric interaction by an own material parameter for each effect. The exact formulation of these quantities as energy independent functions is, however, impossible. Using a set of attenuation coefficients at suitably chosen energies as coefficients for the system of equations the best substitutes are found. The solutions for the investigated example are identical with the original relative to its chemical composition. Such solutions may be of use in connection with neutrons, protons, heavy ions and negative pions. The compounds taken into consideration must, of course, permit such solutions. These facts are discussed in detail by two examples.