Study of the use of sodium thiocyanate as an indicator for three-dimensional dosimetry

Three-dimensional dosimetry allows the determination of dosimetric quantities with a volumetric gradient. With Fricke Gel it is possible to make measurements of this nature due to the restriction of ions in this dosimeter caused by the presence of a gelatinous matrix. When ion indicators are added to Fricke Gel, the diffusion of the ions is further hampered and, in addition, the use of optical measurement techniques for the determination of the absorbed dose becomes possible. In this study, a new ferric ion indicator possibility for Fricke Gel is evaluated. Sodium thiocyanate was added to the Fricke Gel matrix and the effect of this addition was analyzed in a gamma radiation field and in a high-energy electron beam. The obtained results demonstrated the possibility of using this indicator as a binding agent in the Fricke Gel dosimeter. In the gamma irradiation field, the dosimeter showed a linear response with the absorbed dose between 5 Gy and 150 Gy, in addition to presenting visual evidence of the spatial distribution of the radiation field to which it is subjected.