Space charge influence generated by electronic beam on insulator secondary emission

The effect of space charge development on secondary emission of insulators irradiated by an electron beam is studied. Experiments are driven by controlling electron beam energy (keV), current density (A/cm ²), dose of charges (pC), current (pA) and sample temperature. Several effects, not observed up to now in insulator electronic emission studies, are taken into account. Experimental evidence concerns the temporal fluctuations of secondary emission during the experimental sequence, the existence of a critical storage energy from which a non-classical electron-material interaction is observed, the release of breakdown and flashover processes depending on the electrostatic field, the effect of temperature on charge trapping. For the interpretation of these results one needs to know: (1) The spatial beam implanted charge distribution; (2) The effect of the double layer (positive layer in depth corresponding to secondary electron exhausting distance, negative layer due to trapping of the thermalized primary electrons); and (3) The effect of the storage energy in a dielectric under three simultaneous stresses (thermal, electrical, mechanical) on material structural stability