SPACE CHARGING OF POLYMERS BY IRRADIATION WITH LOW-ENERGY ELECTRONS

Experimental studies on space charging of polymers [polystyrene, poly( ethylene terephthalate), polyethylene, polytetrafluoroethylene, polypr opylene, polyimide, etc.] by 40- and 60-keV electrons at beam current densities of 3 or 30 nA/cm(2) under conditions at which the electron r ange is less than the film thickness of the polymer are reported. The processes of charge buildup were studied using the method of a split F araday cup. It was found that prolonged continuous irradiation results in the rear-electrode current attaining some steady-state value that is strongly dependent on the thickness of a blocking layer. No adequat e explanation for the observed quasi-steady-state current was suggeste d.