HIGH-DOSE FILM DOSIMETERS BASED ON BROMOPHENOL BLUE OR XYLENOL ORANGEDYED POLYVINYL-ALCOHOL

Dyed poly(vinyl alcohol) (PVA) films, prepared by a simple technique o f casting aqueous solutions of PVA containing bromophenol blue (BPB) o r xylenol orange (XYO) on a horizontal glass plate, are useful as rout ine high-dose dosimeters. These flexible plastic Elm dosimeters are bl eached when exposed to gamma-ray photons. Absorbed doses should not ex ceed 20 kGy for BPB/PVA film and 90 kGy for XYO/PVA film. The radiatio n-chemical yield (G-value) of both films was calculated and found to b e 0.205 mu mol/J for BPB/PVA and 0.143 mu mol/J for XYO/PVA. The effec ts of irradiation temperature and relative humidity as well as pre- an d post-irradiation storage, on the radiation responses of the films ar e examined. Although the response of these films depends on the irradi ation temperature, these films are highly stable before and after irra diation under different storage conditions and are not affected by hum idity changes in the intermediate range of relative humidity (10-60%).