Congo Red/Polyvinyl Alcohol Film Dosimeter for Gamma Rays and Electrons

Polyvinyl alcohol films containing congo red are useful as gamma and electron radiation dosimeters. Absorbed doses should not exceed 500 kGy. The dose response is rather Iinear in a higher range, e.g., 100 to 500 kGy. The film is relatively stable before and after irradiation for quite a long time against fading, for example, a change of ∼10% in 1 yr following irradiation at room temperature.