Alpha-particle stopping cross section of silicon and germanium

Stopping cross sections of α particles for silicon and germanium have been measured for 0.3 ≤ Eα ≤ 2.0 MeV. The experimental method consists of the elastic scattering of α particles either from a thick Ta backing onto which the stopping element has been evaporated, or directly from the film of stopping element evaporated onto a thick Al backing. The results were analyzed using a three-parameter formula for stopping cross section recently suggested by Brice. With the parameters obtained from a least-squares fit, the formula was found to be useful in calculating the stopping cross sections for energies outside the measurements, at least up to 10 MeV.