Abstract
Abstract Radiochromic dye films were fabricated by casting polyvinyl butyral (PVB) in weakly acidic solution with the leucocyanide of pararosaniline. Calibrated films of 10–25 μm thickness were useful over a response range of about 103–105 Gy, by applying spectrophotometric analysis at the wavelength of the maximum of the radiation-induced absorption band (550 nm). The effects of temperature, pressure, and humidity during curing of the films pointed to the need for carefully controlling these parameters. For casting films at the high altitude of Mexico City (≈ 2500 meters), the optimum conditions are 45–75% r.h. and 20–25° C for a drying period of 72 to 92 hours, when the solvent is a mixture of ethanol and 2-methoxyethanol. The response of films fabricated in this way were compared with those of commercially available PVB and Nylon films. The effects of temperature, humidity, and period of storage on the response of these films were studied in the range from −5 to 60° C and from 11.8 to 96.6% r.h. for up to four months between irradiation and spectral analysis, and within nominal experimental uncertainty (≈ 10%), we found that all the radiochromic films studied can be stored for extended periods under steady-state conditions in the temperature range from −5 to 30° C and from 11.8–75.6% r.h. without correction factors for instability, but under extreme conditions of moisture at elevated temperatures the radiochromic image showed a fading effect on storage.
Published Version
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