THE MILLIMETER-WAVE DIELECTRIC-PROPERTIES OF AL2O3 AFTER IRRADIATION TO MODERATE NEUTRON FLUENCE

Mono- and polycrystalline Al2O3 has been irradiated to 3.5. 1019 f.n/cm2, and the increase in dielectric loss has been measured at 28–38 GHz and 144–146 GHz. Step annealing experiments have been performed between 150 °C and 1100 °C. The recovery of dielectric loss has been analyzed aiming at identifying the defect types affecting dielectric loss. A pronounced recovery step observed at 450–550 °C is explained by F-centres with strong electron-lattice coupling which contribute predominantly to dielectric loss at room temperature. © 1991, Taylor & Francis Group, LLC. All rights reserved.