Design and radiation hardness of next generation solar UV radiometers
Résumé
For next space-based ultraviolet (UV) solar radiometers, we propose a design based on subsystem components that are selected according to lessons learned from previous flying missions and ground irradiation campaigns. UV interference filters inherited from space-based solar missions show strong degradation caused by structural changes that lead to an important decrease of visible light rejection. Wide bandgap semiconductors (WBGS) are used for the photodetectors: innovative metal-semiconductor-metal (MSM) based on Aluminum Nitride (AlN) and Diamond-based PIN photodetectors were developed, characterized and compared to the commonly used silicon photodiode technology (AXUV and SXUV types). Insignificant degradation of the WBGS basedphotodetector performances were observed after exposure to protons of 14.4 MeV energy showing a good radiation tolerance up to fluences of 1x1011 p+/cm2. Onboard calibration strategy based on UV LEDs are used as well to distinguish the detector's drift from inevitable degradations of the optical front filters.