Sol–gel derived copper-doped silica glass as a sensitive material for X-ray beam dosimetry

• Copper-doped sol–gel-derived silica glass rod is studied under X-ray irradiation.
• Rapid radioluminescence remains linear for dose rates up to 30 Gy/s.
• Radioluminescence process involves the same Cu+ states as photoluminescence.
• Optically-stimulated luminescence signal is explored for dose up to 50 kGy.
• OSL stimulation process involves several photons and several intermediate states.

The light emission from a sol–gel-derived Cu-doped silica glass was studied under 10 keV X-ray irradiation using a fibered setup. Both radioluminescence (RL) and optically stimulated luminescence (OSL) were analyzed at different high dose rates up to 50 Gy/s and for different exposure times, yielding accumulated doses up to 50 kGy (in SiO2). Even if a darkening effect appears at this dose level, the material remains X-sensitive after exposure to several kGy. At low dose rate, the scintillation mechanisms are similar to photoluminescence, involving the Cu+ ions electronic levels, contrary to the nonlinear domain (for dose rates higher than 30 Gy/s). This RL, as well as the OSL, could be exploited in their linear domain to measure doses as high as 3 kGy. A thorough study of the OSL signal has shown that it must be employed with caution in order to take the fading phenomenon and the response dependency on stimulation source intensity into consideration.