The effect of temperature on charging behaviour of polyimide subjected to electron beam at vacuum

Abstract

Charge accumulation is one of the main factors leading to electrostatic discharge and restricting the development of spacecraft. This paper investigates the effect of temperature (243–343 K) on the charging behaviour of polyimide in vacuum using electron beam radiation test system. The surface potential distribution shows that there are two charging modes, ‘negative-peak’ mode and ‘negative-crater’ mode. For investigating the charge accumulation mechanism, the space charge experiments were carried out by the method of pulsed electro-acoustic. The thresholds of injection from the polyimide/electrode interface are affected by temperature. Under high temperature (above 323 K), the hole could be easily injected from the polyimide/electrode interface, with the extremely low injection threshold. The incident electrons and the injected holes co-existence and form the ‘negative-peak’ mode. Under low temperature (below 303 K), the area of hole injection from the electrode decreases with the decrease in temperature. The hole injected locally forms an opposing electric field, which makes the surface potential present the ‘crater’ mode. This work shows that the hole injected from the dielectric/electrode interface play a critical role in the charge accumulation process under electron radiation, which has important significance to avoid the spacecraft electrostatic discharge problem.