Dose response of Fricke Gel dosimeters with distinct indicators<i></i>

Fricke solution, composed of ferrous ammonium sulfate in an aqueous solution of sulfuric acid, is used as a chemical dosimeter for gamma rays, X-rays and high energy electrons. The three-dimensional dosimetry has several applications, such as in radiotherapy procedures, imaging diagnosis techniques and internal dosimetry. In this work, the response of Fricke gel dosimeter with two types of indicator was compared. Sodium thiocyanate, a salt not used in dosimetry, and xylenol orange, a well-established indicator, were analyzed as indicators. The studies were performed in a cobalt-60 source. Dosimetric responses of Fricke gel with distinct indicators differ in their sensitivity, that is, the addition of sodium thiocyanate to the gel shifted the saturation point of the gel to an absorbed dose of approximately 300 Gy, while the Fricke gel with xylenol orange presents a saturation of around 30 Gy.