Dosimeter based on silver-nanoparticle precursors for medical applications with linear response over a wide dynamic range

In this Letter the authors study a liquid detector based on Ag nanoparticles for dosimetry purposes. They use two different concentrations of silver nitrate (1 mM AgNO₃) and sodium citrate (1 and 0.1% C₆H₅O₇Na₃) as precursors for the formation of Ag nanoparticles in an aqueous colloidal solution. The authors utilise a linear accelerator to expose the solutions to absorbed doses ranging from 0.5 to 120 Gy and they find that gamma radiation induces the synthesis of Ag nanoparticles already at 2 Gy, when the sodium citrate concentration is lowered to 0.1 . The authors find a correlation between shape/dimension of the Ag nanoparticles and the absorbed dose. More importantly, the authors show that the absorbance peak intensity of the Ag nanoparticles increases with the absorbed dose and that a linear dependence is achieved at the lower sodium citrate concentration.