Effects of Space Environment Factors on Optical Materials

The effects of protons and electrons, as well as thermocycling, on surface morphology and optical properties of beryllium-base reflector and JGS3 optical quartz glass were studied. The energy of protons and electrons was in the range of 60-180 keV, and the thermocycling temperature interval T = 80-403 K. The results showed that after the radiations for a critical fluence of Φ = 6 × 10 1 5 /cm 2 the surface morphology of beryllium-base reflector was damaged severely. The radiations tended to induce spotted pits on the reflector surface with thicker SiO 2 layer and bubbles on that with thinner SiO 2 layer. The surface damage was aggravated by thermocycling following the radiations and affected by grounding conditions. The JGS3 glass was colored evidently after the fluence reached Φ = 10 1 5 /cm 2 for the protons and Φ=5 × 10 1 4 /cm 2 for the electrons. The protons mainly induced the absorption bands at 209 and 220-240 nm and the electrons the bands at 203 and 215 nm. Under the fluence less than Φ = 2 × 10 1 6 /cm 2 , the absorptions increased with fluence monotonically. The E'-type centers were responsible for the absorptions at 203-215 and 220-240 nm.