An empirical test of the Brandt theory which describes the maximum of the proton stopping power

The maximum stopping power for protons, Ssub(m), which occurs at a certain energy Esub(m) is considered. According to the Brandt theory, the product Ssub(m)Esub(m) is a function of only the relative number of target electrons taking part in the stopping process. This theory is compared to all the fitted values from the tables of Andersen and Ziegler (28 targets) using, in addition to the Thomas-Fermi model, the Lenz-Jensen model for the determination of the effective number of electrons. Both models give good agreement with the data, when the best values for the free parameters in the theories are used. (author)