CURRENT TRANSIENTS INDUCED BY FAST ELECTRONS AND BREMSSTRAHLUNG IN POLYETHYLENE FILMS

The kinetics of the current decay in d.c. polarized polyethylene film induced by 6 MeV electron or bremsstrahlung pulses at the ambient temp erature are studied. A strong influence of the external polarizing vol tage on the current transient peak position for X-ray-induced excitati on has been found whilst the lack of such an effect for the electron-i nduced transients has been observed. The mobility of charge species in LDPE has been defined to be 1.7 x 10(-6) m(2) V-1 s(-1) using X-ray p ulsed excitation. The paper also shows electron beam stimulated discha rge currents in the sample and the influence of the absorbed dose due to fast electrons on the current transients induced by subsequent X-ra y pulses in the polarized sample. The occurrence of micro-discharges i s reported in a previously electron beam treated sample during bremsst rahlung excitation of the polarized sample. Copyright (C) 1996 Elsevie r Science Ltd