Effects of ambient temperature on the FXG radiochromic gels used for 3-D dosimetry

Environmental effects on the optical properties of a sensitive radiochromic gel dosemeter; in particular storage, irradiation and measurements temperature were studied. Knowledge of light temperature and other ambient effects help to optimise working conditions and minimize errors. A ferrous-sulphate dosemeter with xylenol orange ion indicator incorporated in a gelatin gel matrix (FXG) was prepared under normal working conditions, and the samples were then kept in closed storage area at different temperature ranging from 5°C up to the gel melting temperature about 35°C. The samples optical absorbance was then measured quantitatively using double beam spectrophotometry. There is a small and steady increase in the absorbance 0.3×10^-3 /°C with increasing temperature until about 30°C when we observe a big jump in the gel absorbance. Finally, additional important behaviour of FXG material was noticed, that is the changes occurred under the influence of rising temperature are reversible which is different from the permanent radiation caused changes.