Space charge formation in gamma-irradiated low-density polyethylene

Energetic ionising radiation can alter the chemical structure of polymeric materials and may also give rise to the presence of trapped charge within the material, the trapping characteristics of which may be influenced by these radiation-induced structural alternations. In the present work, the formation of space charge formation in irradiated low-density polyethylene(LDPE) was investigated using the laser induced pressure pulse (LIPP) technique. Specimens of LDPE, similar to 350 mu m thick, were irradiated in a Co-60 gamma-source in air at ambient temperature to various doses and the results indicate that space charge distributions are dependant on both dose and applied electric stress and the length of time for which the stress is applied.