Neutron irradiation effects in quartz: optical absorption and electron paramagnetic resonance

Optical absorption measurements in the 3-9 eV energy range and electron paramagnetic resonance (EPR) have been performed at 300 K and at 80 K on Sawyer PQ quartz. The effect of the neutron irradiations is to induce the presence of absorption bands at 7.6 eV (E band) at 7.1 eV (D band) and at 6 eV (E' region). The most intense peak of all the spectra is the E band (7.6 eV); its shape is complex and the existence of a double structure can be suggested. The D band is evidenced for the first time in neutron-irradiated synthetic quartz, the authors measurements show that this structure is correlated with the 6.0 eV band. The 'E'' region is complex; in fact, at the highest neutron fluence the optical absorption spectrum reveals the existence of four structures, at 4.7, 5.2, 5.6 and 6.0 eV, where the 4.7 eV band has the same characteristics as the D 0 band, which is present in amorphous silica.