LUMINESCENCE OF NEUTRON-IRRADIATED AMORPHOUS SIO2 - THE 1.9 AND 2.2 EV EMISSION BANDS

Experimental results on the 1.9 and 2.2 eV luminescence bands in neutron irradiated amorphous silica are reported. All the four types in which silicas are usually classified (natural and synthetic, both dry and wet) are considered. Photoluminescence spectra in the 80 to 650 K temperature range, photoluminescence excitation spectra at 80 and 300 K, and spectrally resolved thermally stimulated luminescence are measured. The comparison of the intensity of the 1.9 eV band in the different types of silicas allows us to support one of the models recently proposed for the structure of the emitting center. A first systematic description of the main properties of the 2.2 eV emission band is given.