Usability of aqueous solutions of methyl red as high-dose dosimeter for gamma radiation

The effect of gamma radiation on the organic dye methyl red and its possible use in chemical dosimetry has been investigated. Alkaline and acidic aqueous solutions of this indicator were prepared, and exposed to various gamma doses. The absorbance% in alkaline medium decreased exponentially with respect to the irradiation dose; the data show that the alkaline dye solution could be used as chemical dosimeter for gamma rays in the range between 50 and 6000 Gy.The absorbance% of the acidic dye solution decreases linearly with increasing the irradiation dose up to 200 Gy, and the useful dose range can be extended up to 1250 Gy by addition of 1% ethanol.