Optical properties and photosensitivity of vacuum synthesized Ge-doped sol-gel amorphous SiO2

We report optical and electron paramagnetic resonance investigations of gamma ray irradiation effects in sol-gel Ge-doped amorphous SiO₂. The studied materials have Ge-doping levels up to 10⁴ molar part per million and were densified by two routes differing for the atmosphere: O₂+N₂ or vacuum. The obtained results evidence that irradiation affects matrix sites inducing paramagnetic defects. Furthermore, the comparison between the two densification procedures shows that vacuum atmosphere induces higher radiation sensitivity.