X-ray induced absorption in fused silica containing various amounts of OH.

Characteristics of x-ray-induced absorption spectra in various types of synthetic fused silica (SFS) containing 0.1–77×1018 cm-3 of OH were studied up to an irradiation time of 6 h. Induced absorption in the SFS spectra of irradiation with x ray from a Rh target with a dosage of 2×104 C kg-1 h-1 was reproduced by six Gaussian absorption bands, at 3.8, 4.8, 5.0, 5.4, 5.8, and 6.5 eV, respectively. Intensities of these absorption bands increased with power of irradiation time. The intensities of the 5.8, 5.4, and 5.0 eV bands decreased with increasing OH content at an irradiation time shorter than 2 h. At an irradiation time longer than 2 h, on the other hand, the intensities of each absorption band had a minimum at an OH content of ≈5×1018 cm-3, and increased with increasing OH content at higher OH content. The power of the time dependence had a minimum at an OH content of ≈5×1017 cm-3, and increased with increasing OH content for higher OH-containing samples. [ABSTRACT FROM AUTHOR]