Measurement of backscattering parameters with a pulsed electron beam

Bunches of 1 MeV electrons were made to fall normally on surfaces of graphite, aluminium, copper, silicon and silver and in each case the yield of backscattered electrons was measured using a special type of Faraday cup. The average beam current was kept low enough to avoid any surface heating and also to match the radiation levels that exist in some regions of space. The measured values of backscattering ratios and coefficients are found to be close to the values derived using an empirical relation but slightly higher than those reported earlier for relatively high beam currents.