Fabrication and Property of Film Dosimeter Based on Cellulose Diacetate

The measurement of dose is very important in the radiation physics, radiation chemistry and radiation processing. Cellulose acetate film has been widely used as radiochromic dosimeter in radiation processing with electron beams. However, the common used cellulose acetate film dosimeters are usually influenced by the environmental conditions such as temperature during irradiation, dose rate and post irradiation storage which limited their practical applications. Aiming to improve the stability and application of cellulose acetate film dosimeter during the determination of γ-radiation dose, the cellulose diacetate (CDA) prepared by homogenous acetylation of cellulose in ionic liquids was utilized as raw material, and a clear CDA radiochromic film with good performance was obtained successfully by a casting method. Firstly, the suitable conditions, such as temperature, concentration and drying time for the preparation of CDA film were studied. Furthermore, the gamma radiation effect on the resultant CDA film and stability of radiochromic film during measurement was investigated. Owing to the radiation induced discoloration mechanism of CDA, the absorbance of the CDA film at a wavelength of 270 nm had a good linear relationship with the absorbed dose. The dose rate, the substitution degree of CDA and the irradiation atmosphere had no significant effect on the working curve of the CDA film dosimeter. The range of dose detection was 50-400 kGy, and its extended uncertainty was 8.8% (K=2), with a good measurement stability in 24 h after irradiation. Additionally, the CDA film had good stability during irradiation, the structure and substitution degree of CDA remained unchanged during the irradiation and this can meet the industrial requirements for the radiation dosimeters. The as-prepared cellulose-based radiochromic film is a promising dosimeter for the measurement of γ-ray dose.