Radiation-induced conductivity in polymers under continuous irradiation

As a result of extensive experimental investigations of radiation-induced conductivity in low density polyethylene (LDPE) due to a step-function irradiation, it is established that the induced current goes through a maximum before reaching its steady-state value in full agreement with recent theoretical analysis. For the polymer studied the steady-state conductivity is at least six times less than its maximum value while the times of equilibration are extraordinary high (accumulated doses in the range of 1x105 to 1x106 Gy). It is implied that experimental data reported so far for low to intermediate dose rates (<= 1 Gy/s) refer primarily to a maximum rather than a steady-state conductivity as originally thought. (author)