Response of commercial window glass to gamma doses

This work reports experimental results of an effort undertaken to identify and characterize the radiation-induced defects created during gamma (gamma)-irradiation of commercial glass on the basis of optical absorption measurements performed before and after irradiation. It is assumed that the induced absorption band formed after gamma-irradiation of soda-lime-silica (SLS) glasses are created by some hole-type color centers related with non-bridging oxygen ions (NBO-) located in different surroundings. Results have been discussed taking into consideration the presence of iron as impurity in the glass structure. It is well known that the absorption bands of Fe 31 in the visible range is at 420-440 nm, in this study the band at 430 nm was followed. Also, the optical gap variations (Delta E-opt) induced by gamma-irradiation were investigated. Moreover, the study illustrated that the optical absorption sensitivity and the mechanism of fading either at room or elevated temperature has been discussed in relation to successive irradiation doses, dose rate and thickness. The results are discussed on the basis of the annihilation mechanisms of induced irradiation defects. (c) 2007 Elsevier B.V. All rights reserved.