Measurement of residual space charge distribution in gamma-irradiated polyethylene

The paper discusses the residual space charge distribution in gamma-irradiated polyethylene formed with DC voltage, which was measured using the pulsed electroacoustic (PEA) method. The PEA method is one of the advanced nondestructive techniques used to measure the space charge distribution with a high sensitivity and reproducibility. From the experimental result, it became clear that a large amount of positive charges existing near the cathode in gamma-irradiated polyethylene enhance the electric field at the cathode interface. Under short circuit conditions, the strength of this electric field by the space charge is sometimes more than two times the applied field. On the other hand, almost no space charge was observed in the nonirradiated sample