用于深层充电评估的卫星介质电导率测量技术研究

Measurement of dielectric conductivity for assessment of deep charging

准确测量得到卫星介质材料的电导率对于卫星深层充电危害评估具有重要意义。在电荷贮存衰减法的基础上,文章提出了一种获得介质材料暗电导率和辐射诱导电导率的试验测量和数值计算方法,即采用90Sr-90Yβ放射源,在温度为20℃、束流密度为5pA/cm2的条件下对卫星常用的聚酰亚胺材料进行辐照试验,通过测得的材料表面电位随时间的变化曲线,拟合得到材料的暗电导率和辐射诱导电导率。该方法已在某卫星产品的充电评估中得到应用,计算结果与模拟试验结果符合较好。

The deep charging effect of dielectrics is one of main factors leading to satellite failures.The conductivity is a key parameter which determines how the accumulated charge will be dissipated through the dielectric materials.The exact measurement of the dark conductivity and the radiation induced conductivity is essential to the hazard evaluation of the deep charging.On basis of the charge storage and decay method,the measurement and the numeirical caculation of the dark conductivity and the radiation induced conductivity are discussed in this paper.The irradiation tests of two materials are performed at temperatuer of 20 ℃,with irradiation intensity of 5 pA/cm2by using 90Sr-90Y β source.The surface potential of materials varying with time is measured and the conductivity is calculated by curve fitting.This method was used in charging assessment of a satellite,and the calculated result is in good agreement with the test result.