Radioluminescence of Ge-doped silica optical fibre and Al2O3:C dosimeters

Using an electron accelerator producing a 6 MV X-ray photon beam several experimentally observed excitation phenomena that are associated with radioluminescence (RL) have been investigated, the signal originating from a Ge-doped silica optical fibre and commercial nanoDot Al2O3:C dosimeters. Using PMMA optical communication fibres the RL signals have been guided from the beam-delivery room out to the readout instrumentation that has been located beyond the concrete maze providing effective radiation shield. Ge-doped silica fibre memory effects and afterglow (phosphorescence) were compared with that of the commercial Al2O3:C dosimeter. Immediately following RL, observation was made of the decay curves of the afterglow signal of Al2O3:C. Conversely, there was little practically observable afterglow for the Ge-doped fibre used for the majority of present investigations (the dopant concentration of this being 3.6 wt %). Among three different concentration of Ge-doped fibres that were subsequently investigated in a follow-up study, the intensity of afterglow was found to be greatest for the more highly doped concentration (7.0 wt % Ge), with progressive reduction of the effect for the Ge 4.7 wt % and Ge 3.6 wt % fibres. These observations can be compared against the much more marked RL memory effect observed using the Al2O3:C chips. Current results point to the Ge-doped silica optical fibre being a highly promising candidate for real-time RL dosimetry and sensing.