Investigation of TL properties of sand collected from sewage sludge as an “in situ” dosimeter in radiation disinfection

Thermoluminescence (TL) properties of sand, collected from sewage sludge, were studied after extensive cleaning procedures. In the sand samples treated with either hydrogen peroxide (H2O2) or hydrofluoric acid (HF), there was a prominent TL peak at about 220°C after γ-irradiation and 120°C, 20 min post-irradiation annealing treatment. The dose vs TL response curves in hydrogen-peroxide-treated and HF-treated sand samples were found to be linear up to 30 and 100 Gy, respectively, beyond which they were supra-linear. The extent of post-irradiation fading in the sand sample, which was treated with H2O2 and post-irradiation annealed at 120°C for 20 min, was observed to be 8% after 21 days, while no detectable fading was observed for the sample which was HF treated and annealed at 120°C for 20 min after γ-irradiation. Therefore, H2O2- as well as HF-treated sludge sand samples could be considered for use as in situ TL dosimeters for radiation disinfection of sewage sludge.