In Situ Luminescence Measurement from Silica Glasses Irradiated with 20keV H^- Ions

A new low-energy negative-ion induced luminescence setup was recently developed at the injector of the GIC4117 2\times1.7 MV Tandem accelerator in Beijing Normal University. In situ luminescence measurements are performed on silica glass by using 20 keV H^- ions at room temperature. Gauss fitting of the spectra revealed six overlapping components at about 2.7 eV, 2.4 eV, 1.9 eV, 1.8 eV, 4.2 eV, and 3.6 eV, which except for the new observed emission band at 3.6 eV are assigned to the creation of type II oxygen-deficient centers, E' centers, non-bridging oxygen hole centers with different precursor states, and type-I oxygen-deficient centers. The fitted results of the saturation concentration show that self-trapped exciton recombination at type-II oxygen-deficient centers is the main luminescence emission process. The evolution of the luminescence intensity and full width at half maximums as a function of ion fluence is also discussed. It is found that the number of recombination centers reaches its maximum at lower fluence, and the area ratio between blue bands and red bands is much lower than that under high energy H^+ ion irradiation.