Abstract
A technique is presented for measuring collision stopping powers of 5 to 50 MeV electrons. Measurements were made at 10 and 20 MeV with slabs of C, Al and Cu ranging in thickness from 0.5 to 1.5 g cm-2. A large, nearly totally-absorbing NaI detector was used to measure the energy distribution in the beam with and without an intervening slab. Detailed Monte Carlo simulations of the full experimental geometry were done. The offset between the simulated and experimental distributions was determined by precise fitting and was used to obtain the stopping power. Reduction of the drift and improved energy linearity should allow stopping power measurements with an accuracy of 1% or better.