Characteristics of radiation-induced coloring of high-purity vitreous silica at elevated temperatures

Exposure of high-purity vitreous silica to ionizing radiation causes the appearance in its spectrum of an absorption band in the ultraviolet range with a maximum at 215 nm due to E1' color centers on three-coordinate silicon. The concentration of E1' color centers and the intensity of induced absorption increase monotonically with irradiation dose. Such investigations have been carried out at and below room temperature. The purpose of the present paper is investigation of the radiation-optical properties of high-purity vitreous silica of grades KU-1 (type III) and KUVI (type IV) in the range 20-300 degrees C. The concentration of OH groups was ∼0.1 mass% in vitreous silica KU-1 and 0.001 mass % in vitreous silica KUVI. The concentration of metallic impurities did not exceed 5 x 10-4 mass %