Effect of perchloric acid on the performance of the Fricke xylenol gel dosimeter

• Perchloric acid enhances the radiation sensitivity of the ferrous xylenol orange gel.
• The gel, either with or without the acid, shows a linear dose response in the range 1–15 Gy.
• Storage environment factors need to be well controlled to minimize dose errors.

The conventional ferrous xylenol orange (XO) gel (FXG) dosimeter is being wildly investigated for radiotherapy dose measurements. Upon irradiation, its color turns red due to oxidation of Fe2+ into Fe3+, which forms a complex with xylenol orange. The effect of perchloric acid (PCA) on the dosimetric properties of the gel in the dose range of 1–15 Gy was investigated using visual spectrophotometry. FXG-PCA responds to radiation dose linearly and exhibits higher radiation sensitivity than the conventional gel dosimeter. PCA in a concentration of 20 mM enhances the radiation sensitivity ~44%. Stability of the absorbances of both the gels during storage under various conditions was investigated, and the uncertainty of dose measurements was estimated.