Fabrication of a flexible polycarbonate/porphyrin film dosimeter for high dose dosimetry

Dyed polycarbonate (PC) Radiochromic films with 20 μm thickness were prepared by casting of organic solution of PC containing 0.5 wt.% tetrakis (pentafluorophenyl) porphyrin (TPPF₂₀) on a glass petri dish. Characterization of the film as a routine dosimeter was studied. On subjecting PC/TPPF₂₀ film dosimeter to gamma radiation, a gradual decrease in the color of films was observed. The sensitivity of these films and the linearity of dose-response curves were studied under ⁶⁰Co γ-rays expose in dose range of 0-100 kGy. The results were compared with the commercial and non-commercial dosimeters. Experimental parameters including humidity, temperature and pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were examined. The maximum absorbance of soret band of TPPF₂₀ had a bathochromic shift and appeared at 414 nm which remained intact in the investigated dose range. The dyed films characteristics were found to be stable enough in media with high degrees of temperature and humidity. The results indicate that radiation induced decoloration of PC/TPPF₂₀ films can be reliably used in high dose dosimetry.