Dosimetric properties of gamma- and electron-irradiated commercial window glasses

Two different types of window glasses have been investigated as possible routine dosimeters in the range of 1-50 kGy. Glass samples were irradiated with 3.4 MeV and 8.4 MeV electron beams, and the results compared With those obtained by (60)Co gamma irradiation. Due to the strong optical absorption at wavelengths < 3 10 run, even at low closes, Optical measurements were limited to the range 320-700 nm. In both types of glasses, irradiation induced two absorption hands around 410 and 600 run the intensities of which are proportional to close: the 600 nm hand being less sensitive to radiation. These hands have been attributed to non bridging oxygen hole centres existing in two different configurations. Because of the rapid fading of the optical absorbance observed at room temperature immediately after irradiation (> 15% in two days), the samples underwent it post-irradiation thermal treatment (150 degrees C For 20 min) to improve the stability of absorbance. The fading characteristics of the irradiated and thermally treated glasses, kept in the dark at room temperature, were studied for several weeks. A fast decay, whose intensity depends oil the type and energy of the ionizing radiation, wits observed for few clays after irradiation and thermal treatment, followed by a much slower decay. The results Show that this kind of material could be used as routine dosimeters within it certain dose range, its long its proper calibrations are made for each batch of glass and the appropriate precautions are taken when doing calibration and performing routine dosimetr