Measurements of secondary electron-emission coefficients and cathodoluminescence spectra for annealed alumina ceramics

To improve the insulating capability of alumina ceramics for use in high-power vacuum devices, it is necessary to clarify the electronic states of ceramics. The dielectric breakdown strength of an alumina ceramic surface depends not only on the secondary electron emission, but also on the electronic states of the oxygen vacancy existing adjacent to the ceramic surface. Secondary electron emission SEE.coefficients and cathodoluminescence CL.measurements were performed on several kinds of alumina ceramics using a scanning electron microscope SEM.. The samples were compared under the conditions of annealing and X-ray irradiation. The influences of annealing and X-ray irradiation on the SEE coefficients and CL spectra were investigated. q1999 Published by Elsevier Science B.V. All rights reserved.