PRELIMINARY-RESULTS OF COMBINED THERMO-LUMINESCENCE AND THERMALLY STIMULATED CURRENT MEASUREMENTS ON AN ADDITIVE FREE POLYETHYLENE

Samples of additive free low density polyethylene have been irradiated at -180 and -130 degrees C with 1 keV electrons. The sample arrangeme nt was such that simultaneous measurements of thermally stimulated dis charge currents (TSDC) and luminescence (TL) were possible and these t echniques were used to observe effects of surface charge relaxation. T he resulting spectra were similar in some respects to those obtained b y other workers using either higher electron energies, which create bu lk charges, and higher irradiation temperatures, or using X- or gamma- radiation to create internal charge. In particular some of the TL peak s in the spectra obtained by the present authors were observed in simi lar regions and a current reversal seen in the TSDC spectrum obtained at the higher irradiation temperature (-130 degrees C) was also observ ed by another worker but for material irradiated at above room tempera ture. The current reversal is most likely to be associated with charge movement in the bulk rather than across the sample surface.