Influence of Atomic Oxygen Irradiation on Secondary Electron Emission Yield of Polyimide Films

We studied the measurement of secondary electron emission (SEE) of metal and insulating materials used for satellite thermal insulation or other such purposes. The SEE yield measurement is very important for analyzing charge accumulation on satellite surfaces in a space environment because electron emission related to irradiated electrons influences the amount of surface charge. We considered degradation phenomena of surface materials for spacecraft caused by radioactive rays. Those SEE yields might change for a nondegradation sample. We measured the SEE yields of surface materials for spacecraft that are treated using the degradation process. In preparation of the degradation sample, the samples were irradiated by atomic oxygen (AO) to simulate degradation in a space environment. We take three irradiation conditions and two irradiation methods related to a GEO orbit and operating period. This report introduces the measurement results of the reference material: polyimide films. We discuss the relationship between the SEE yields and sample degradation when irradiated by atomic oxygen. Furthermore, we consider the effect of different AO irradiation methods: the laser detonation method and the plasma asher method.