Photothermal/photoacoustic method for in situ evaluation of radiation-hardened polyimide films

A non-contact, non-destructive method is used to determine viscoelastic and thermal transport properties of a DuPont Kapton film before and after neutron irradiation to determine the changes that would be expected to occur in a nuclear reactor environment. The results demonstrate general capabilities for in situ, non-destructive evaluation (NDE) of radiation-induced material degradation. The specific application demonstrated is evaluation of insulation materials to be used in a superconducting magnet design in the International Thermonuclear Experimental Reactor (ITER). (orig.)