Irradiation effect on sapphire for optical window

The sapphire is irradiated by different rays (such as γ-ray, X-ray) and the ion currents(such as electrons, protons, etc.) when used in space, thus the performance properties are decreased. In this paper, the sapphire is irradiated by 60Co source and electron current, and the optical and structural properties are studied after the irradiation. The surface roughness, the absorption and fluorescence spectroscopy are tested before and after the irradiation. γ-ray irradiation has a little effect on the surface roughness, but the electron current irradiation makes the surface roughness increase greatly. The absorption spectrum indicates that the sapphire shows absorption peaks in the UV-visible band, such as 206, 238, 300 and 330 nm. And 335 nm, 410 nm and other fluorescent luminous peaks are found in the fluorescence spectrum. Finally, the cause to the absorption peaks is analyzed and the concentration of the color center before and after the irradiation is calculated.