Effects of a Simulated High-Energy Space Environment on the Ultraviolet Transmittance of Optical Materials between 1050 Å and 3000 Å

Abstract

Transmittances of LiF, MgF₂, CaF₂, BaF₂, Al₂O₃, and fused SiO₂ were measured from 1050 Å to 3000 Å before and after irradiation by 10¹⁴ electrons/cm² first at 1.0 MeV and then at 2.0 MeV. Similar measurements were made with 10¹⁴ electrons/cm² at 2.0 MeV using Al₂O₃ to shield fused SiO₂, ADP, calcite, and Corning glass filters 9–54 and 7–54 from the direct electron beam. The electron energy and dose represent what one might expect to encounter in the artificial radiation belt after one year in a circular, near polar orbit at 1400 km. From these measurements it is concluded MgF₂, BaF₂, and Al₂O₃ have the greatest potential for space applications in the uv.