Optical absorption in the 3.5 to 6.5eV spectral range, and photoluminescence in the 4 to 8eV range, were studied in neutron-irradiated synthetic crystalline quartz as a function of the temperature and neutron fluence. Gaussian deconvolution of the radiation-induced absorption spectrum in the 4.5 to 6eV region revealed a complex structure, with 5 distinct components that peaked at 4.85, 5.06, 5.35, 5.62 and 5.96eV. The complexity of the absorption pattern was reflected by corresponding photoluminescence spectra in the 5eV region. A detailed analysis of the emission spectra as a function of the excitation energy indicated the presence of emission bands which were centered at 3.91, 4.23 and 4.46eV, and excited to 5.25, 4.83 and 5.03eV, respectively. Excitation of the 5.62 and 5.96eV absorption peaks did not produce emissions. The features of the 4.23 and 4.46eV bands were very similar to those of the intrinsic emission which was already well known for amorphous SiO2. It was suggested that there was a possible correlation between these bands and the intrinsic center. The 3.91eV band had no corresponding feature in amorphous SiO2, and it was assumed that the responsible defect was specifically related to the crystalline structure. The emission spectra which were excited in the E absorption band (at about 7.6eV) were suggested to indicate a weak band that was centered at 4.83eV. Its dependence upon the neutron dose implied that it should be attributed to an intrinsic center that was different to those which were responsible for emissions in the 3.8 to 4.5eV region.

A.Corazza, B.Crivelli, M.Martini, G.Spinolo, A.Vedda: Physical Review B, 1996, 53[15], 9739-44