铝屏蔽间隙对聚醚醚酮高能电子辐射下介质深层充电特性的影响

A metal shielding layer is adopted in the outer layer of spacecraft power system, conductive rotating mechanism, and other components for radiation protection. And the shielding layer will affect the charging and discharging characteristics of the dielectric under electron irradiation. In this paper, polyether-ether-ketone(PEEK) was used as the research object. By setting the gap between the aluminum shielding layer and the dielectric, some two-dimensional dielectric deep charging simulation models with different gaps are constructed. The influence of different aluminum shielding gaps on the deep dielectric charging characteristics was simulated by a finite element analysis method. Besides, the effect of the operating voltage on the dielectric charging process also was simulated and analyzed. The results show that the smaller the aluminum shielding distance is, the more serious the charge accumulation on the surface of the dielectric will be, and the accumulation amount increases with the increase of the irradiation time. When the aluminum shield contacts the dielectric, the amount of charge accumulation on the surface of the dielectric decreases rapidly, and the instantaneous surface charge changes. As time increases, the surface charge is negligible and substantially constant, and the internal charge of the dielectric is also reduced. At the same time, positive and negative space charge peaks appear near the aluminum shield side. When the aluminum shield does not contact the dielectric and the operating voltage is positive, the surface charge is reduced; when it is negative, the surface charge is increased. When the aluminum shield contacts the dielectric or the distance is long, it is beneficial to alleviate the charging and discharging effect of the dielectric and improve the stability of the spacecraft.