Methyl thymol blue solution and film dosimeter for high dose measurements

Abstract

A novel radio-chromic solutions and polyvinyl alcohol (PVA) films with different concentrations of methyl thymol blue (MTB) dye have been investigated and studied for high dose applications. The MTB dosimeters were exposed to irradiation using gamma ray 60Co source from 2.5 to 50 kGy for film, and from 0.10 to 2.5 kGy for solutions. The radio-chromic dosimeters were investigated using ultraviolet visible (UV–Vis) spectrophotometry. The effect of MTB dye concentration, relative humidity, and stability of the dosimeters were investigated. The results show that the dose response sensitivity of the dosimeters improved significantly with increasing the absorbed dose and MTB dye concentrations. The un-irradiated and irradiated dosimeters show a perfect stability for one week. Hence, these films can be used as dosimeters in industrial radiation processing. The study shows that the useful dose range is in the range of 2.5–20 kGy and 0.1–1.2 kGy, for film and solution dosimeters, respectively.

Keywords

• Radio-chromic dosimeter
• Methyl thymol blue
• Color bleaching
• Absorbance
• High dose dosimeter