Dielectric discharge of PI material irradiated by 40MeV -protons

The role of electrons penetrate deeply inside dielectrics has been known for years. However, as the increasing desire of long-term deep space missions such as lunar surface exploration have the potential of spacecraft exposure in high fluxes of solar energetic protons, which demands the understanding of proton penetrating mechanism. This paper describes dielectric discharging of PI material irradiated by 40MeV -protons. Discharge of PI materials with different thickness of 21.5mm, 15.5mm, 13.6mm and 8.2mm were investigated. For PI films with thickness of 21.5mm, 15.5mm, and 13.6mm, proton discharges were firstly triggered as the protons reached fluence of 1.2×1012p/cm2 , 2.7×1012p/cm2 and 1.3×1013p/cm2, respectively. No discharge was achieved for PI film with 8.2mm thickness. Besides, discharge events originated by secondary electrons were also achieved during irradiation.