Analysis of internal charge distribution in electron irradiated polyethylene and polyimide films using a new experimental method

• Published in: Journal of physics. D, Applied physics Applied physics, 2008-10, Vol.41 (20), p.205417-205417 (8)
• Main Authors: Perrin, C, Griseri, V, Inguimbert, C, Laurent, C
• Format: Article
• Language: English
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Engineering Sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/41/20/205417

The charge distribution in low density pyethylene and polyimide films under a quasi-mono-energetic electron beam irradiation in the range [5-400 keV] is analysed using a new experimental set-up based on the pulsed electro-acoustic (PEA) method. The device allows measurements without any physical contact between the excitation electrode used in the PEA method and the irradiated surface which remains at a floating potential during the entire duration of the experiment. This special configuration makes it possible to study bulk as well as interface phenomena. In particular, emission of charges from the irradiated surface to the vacuum is in evidence as well as charge injection from the ground electrode to the bulk. The time-dependent charge distribution during irradiation is approached by combining a Monte Carlo toolkit for modelling radiation transport in matter in conjunction with a macroscopic description of charge transport based on the concept of a radiation-induced conductivity generated by the injected electrons. Although the macroscopic description yields a fair agreement with the experimental data, it fails to depict the detailed shape of the charge distribution, thereby calling for a microscopic, bi-polar model.