Silica glass samples were irradiated with 1.157 GeV 56Fe ions to fluence of 0.5×1012

1×1012 and 3.8×1012 ions/cm2.The radiation-induced defects were examined by ultraviolet-visible(UV-Vis)

photoluminescence(PL) spectroscopy and electron paramagnetic resonance(EPR) measurements.Various defects such as E’ centers

non-bridging oxygen hole centers(NBOHC) and oxygen deficient centers

ODC(II)

were induced by the irradiation in production cross-sections of 90-140 nm2.The number densities of the defects increased with the fluence and came to saturation at high fluences.It was found that E’ center and NBOHC were created simultaneously from the scission of strained Si-O-Si band.The PL results showed that the intensity of α and γ band increased with the fluence and tended to saturate at high fluences

while the intensity of β band decreased with increasing fluence.It was concluded that β band belonged to an intrinsic defect in silica glass.EPR measurement confirmed the production of E’ centers with a production cross-section of 138 nm2

which was similar to that found in the UV-Vis measurement.