High-dose film dosimeters based on bromophenol blue or xylenol orange dyed polyvinyl alcohol

Dyed poly(vinyl alcohol) (PVA) films, prepared by a simple technique of casting aqueous solutions of PVA containing bromophenol blue (BPB) or xylenol orange (XYO) on a horizontal glass plate, are useful as routine high-dose dosimeters. These flexible plastic Elm dosimeters are bleached when exposed to gamma-ray photons. Absorbed doses should not exceed 20 kGy for BPB/PVA film and 90 kGy for XYO/PVA film. The radiation-chemical yield (G-value) of both films was calculated and found to be 0.205 mu mol/J for BPB/PVA and 0.143 mu mol/J for XYO/PVA. The effects of irradiation temperature and relative humidity as well as pre- and post-irradiation storage, on the radiation responses of the films are examined. Although the response of these films depends on the irradiation temperature, these films are highly stable before and after irradiation under different storage conditions and are not affected by humidity changes in the intermediate range of relative humidity (10-60%).