Eosin dyed poly(vinyl butyral) films for high-dose radiation dosimetry

Abstract

Eosin dyed poly(vinyl butyral) (PVB) films were prepared by casting the alcoholic solutions of PVB incorporating Eosin dye with or without chloral hydrate on a horizontal glass plate. These flexible plastic film dosimeters are bleached when exposed to n -ray photons. Eosin/PVB films are useful as routine high-dose dosimeters where the maxima of the useful dose ranges are between 120 and 450 kGy, depending on Eosin and chloral hydrate concentrations in the film. The radiation-chemical yield ( G -value) of films was calculated to be in the range from 0.01 to 0.03 mol/J, where it increases with the increase of concentration of Eosin in the film. The type A uncertainty of dose measurements using Eosin/PVB films at two standard deviations (2 σ , approximately equal to 95% confidence limit) was found to be - 5.4%. The effects of relative humidity during irradiation as well as pre-and post-irradiation storage on the radiation response of films are studied. Although the response of these films depends on relative humidity during irradiation, they are highly stable for long times after irradiation when stored in dark or light.