Secondary Electron Emission of MgO Crystals Bombarded by Relativistic Electrons

Abstract

The yield of single crystals of MgO has been determined at a primary energy of 1.3 Mev, utilizing a modification of the ``sandwich'' technique developed earlier for investigating the secondary electron emission of metals at high primary energies. The value of δ for Al was measured concurrently under identical conditions. The accumulation of surface charges usually encountered with insulators is prevented by the bombardment‐induced conductivity of MgO. The influence of multiple scattering and energy loss of the primary beam, as well as of δ‐ray production, must be considered when the targets are relatively thick as in the present case. An empirical correction for normalizing the thick target measurements to thin target conditions was determined. The result is: δ_MgO=0.09±0.02 as compared with δ_Al=0.023±0.003.