Development of new chemical dosimeter for low dose range

Accurate measurement of low dose radiation in complex systems is of utmost importance in radiation biology and related areas. Ferrous Benzoic acid Xylenol orange (FBX) system is being widely used for measurement of low dose gamma radiation because of its reproducibility and precision. However, an additional step, i.e., dissolution of benzoic acid in water at higher temperature followed by cooling at room temperature is involved for the preparation of this dosimeter. This makes it inconvenient as a ready to use dosimeter. In the present work, the organic molecule, sorbitol has been used for measurement of low doses of radiation. The advantages of using sorbitol are its ready availability and instantaneous water solubility. Owing to its dissolution at room temperature, possible errors those are involved in calculation of dose due to thermal oxidation of ferrous ions during preparation of the FBX dosimetric solution could be made insignificant in the proposed dosimeter. In the present system, sorbitol acts as radiolytic sensitizer for the oxidation of ferrous ion, and xylenol orange forms a 1:1 complex specifically with ferric ions. Thus, the analytical detection limit of ferric ions is enhanced compared to other systems. Final composition of the dosimetric solution is; 0.5 mol/m3 xylenol orange, 10 mol/m3 sorbitol and 0.2 mol/m3 ferrous ion in 50 mol/m3 sulfuric acid. Radiolytic sensitization in combination with analytical enhancement of the ferrous based system, allows us to measure radiation dose in the range of 0.05 Gy–12 Gy with ease and high reproducibility.

► Low dose measurements in the range of 0.05 Gy to 12 Gy can be measured with excellent reproducibility using the Ferrous Sorbitol Xylenol Orange system.
► Dose measurements can be done at 549 nm using visible light spectrophotometer and the color change on absorbance of dose can be visually observed.
► The solution of FSX can be easily prepared and requires only accurate weighing of the reagents, no complex reaction methods or costly reagents are required to prepare the solution. The solution once prepared can stay up to 1 month under refrigerated conditions.