The radiochromic indicator using methyl red dye solution as a high-dose gamma-ray dosimeter application

The radiochromic indicator using the methyl red dye solution has been studied as a high-dose gamma-ray dosimeter. The indicator has been tested by irradiating using gamma rays with a ⁶⁰Co source. The radiation dose was varied from 5 to 100 kGy with a dose rate of 5.5 kGy/h. The color change of the indicator solution caused by the radiation was characterized by using a UV-Visible spectrophotometer and a camera photograph. In addition, the color stability of the indicator is also studied by observing the effect of time and the storage in light and dark conditions. The effect of time after irradiation on the color of the solution has also been investigated. The methyl red solution indicator showed a radiochromic phenomenon color changes from red to dark red for a dose of 5-20 kGy, faded gradually then became colorless at a dose of 25-100 kGy. These color changes correspond to the peak of the UV-Visible absorbance spectrum at a wavelength of 492 nm. The color of the indicator solution is more stable if kept in dark conditions than in the light conditions. The color of the solution also shows its stability for up to 12 days after irradiation. These results conclude that the indicator solution of methyl red can be used as a dosimeter for gamma rays in the dose range of 5-40 kGy.