Improved procedure for calculating the collision stopping power of elements and compounds for electrons and positrons

This paper is an addendum to an earlier paper which described a procedure and provided the data base for the quick-and-easy calculation of electron and positron collision stopping powers. The procedure makes use of Bethe's stopping-power formula and Sternheimer's theory of the density effect, and involves a parametrization such that some parameters depend only on the particle energy and all others on the properties of the stopping material. Using the data provided, the stopping powers can easily be evaluated with a hand-held scientific calculator. The data base for 278 materials has now been updated through an improved evaluation of the density effect within the framework of Sternheimer's theory. The use of the new instead of the old data base can result in stopping-power changes as large as 1-2%. (author)