Application of concentrated TiO2 sols for γ-ray radiation dosimetry

Upon exposure to γ-radiation, a concentrated TiO₂ sol changes from colorless to deep blue with an absorption maximum at 540 nm. The absorption has been assigned to trapped electrons or Ti³⁺ states in the solid matrix based on its spectroscopic similarity to the samples irradiated with UV light. Unlike the conduction-band electrons generated from direct excitation by UV radiation, the origin of the trapped electrons during γ-ray irradiation may be traced to a series of reducing species produced by the high energy electrons, which in turn, are the direct result of γ-irradiation. As the absorption intensity is linearly related to the duration of exposure to γ-radiation, it may have an application in γ-ray dosimetry. The sensitivity of its dosage response has been found to be influenced by the semiconductor particle concentration and the dispersing solvent.