Ionization Loss and Straggling of Fast Electrons

Abstract

The most probable energy loss of 9.6- and 15.7-Mev electrons in samples of about one gram per ${\mathrm{cm}}^2$ of beryllium, polystyrene, aluminum, copper, and gold has been measured. The losses measured were of the order of one Mev, and the resolution of the apparatus made possible an accuracy of 20 kev. The observed distributions of energy losses are found to be in good agreement with the Landau straggling calculations for the light elements. For the heavier elements there is a spreading of the distribution introduced by radiation and $K$ electron effects. Calculations made by Yang and Kennedy for gold, including these effects, check well with the experimental data.