SEARCH FOR RADIATION-INDUCED ELECTRICAL DEGRADATION IN ALUMINA DURING SPALLATION-NEUTRON IRRADIATION

de and ac electrical conductivity of alumina and sapphire were measured during irradiation with spallation neutrons at the Los Alamos Spallation Radiation Effects Facility to a fluence of about 0.02 dpa. Both ac and de voltages were applied during irradiation at 395, 615 and 655 degrees C in an attempt to measure radiation-induced electrical degradation (RIED). RIED-like effects were observed in the evacuated AC capsules, but no RIED was observed with the de capsules in about 1 atm of argon gas. The de measurements showed an initial high increase in conductivity followed by a continual decrease with increasing fluence. We believe that postirradiation conductivity measurements must be made to confirm the observed current increases in the ac capsules.