Title :
Kerr electro-optic field mapping measurements in electron-beam irradiated polymethylmethacrylate
Author :
Hikita, Masayuki ; Zahn, M. ; Wright, K.A. ; Cooke, C.M. ; Brennan, J.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., MIT, Cambridge, MA, USA
fDate :
10/1/1988 12:00:00 AM
Abstract :
To understand electron-caused discharges along insulating solid surfaces on spacecraft as well as in solids, Kerr electro-optic field mapping measurements have been performed in electron-beam-irradiated polymethylmethacrylate. The accumulated trapped charge results in large self-electric fields of the order of 1 to 3.5 MV/cm. Measurements were done at electron-beam energies up to 2.6 MeV at low (20 nA/cm2) and high (300 nA/cm2) current densities and for sample thickness of 0.635, 0.95, 1.27 and 2.54 cm. It was found that volume breakdown through the electron charged region may occur spontaneously when accumulated charge levels are high. Typically at breakdown the net charge density magnitude exceeded 1 μC/cm2 and internal fields exceeded 1.8 MV/cm. Charge dynamics during electron-beam irradiation was also analyzed on the basis of a simple model consisting of the continuity and Poisson´s equations including charge generation and radiation-induced conductivity
Keywords :
Kerr electro-optical effect; field plotting; materials testing; organic insulating materials; polymers; static electrification; surface discharges; 0.635 to 2.54 cm; 2.655 MeV; Kerr electro-optic field mapping measurements; PMMA; Poisson´s equations; accumulated trapped charge; charge density; charge generation; continuity equations; current densities; electron charged region; electron-beam energies; electron-beam irradiated polymethylmethacrylate; electron-beam irradiation; electron-caused discharges; insulating solid surfaces; internal fields exceeded; model; radiation-induced conductivity; sample thickness; self-electric fields; spacecraft; volume breakdown; Current measurement; Density measurement; Electric breakdown; Electron traps; Energy measurement; Insulation; Performance evaluation; Solids; Space vehicles; Surface discharges;
Journal_Title :
Electrical Insulation, IEEE Transactions on
