Estimation of the difussion properties of Fricke gel dosimeter

JOSÉ VEDELAGO; ANDRÉS QUIROGA; SEBASTIAN TRIVIÑO; FACUNDO MATTEA; MAURO VALENTE

Pucón

Conferencia; VI Conferencia de Física Médica en la Frontera; 2018

Oral Presentation: There are two main of gel dosimeter types for ionizing radiation detection. One of the them consist on monomers combination with radiation induced polymerization properties. The other type is based on Fricke solution within a gelatin matrix for three dimensional dose distribution determination. As a drawback, ferric ion diffusion is a well known problem and appropriate readout methods are needed to overcome this issue. The present work describes a mathematical method together with its computational algorithm for the estimation of the diffusion coefficient of Fricke gel dosimeters. Samples were prepared in layer-type containers optimized for transmittance imaging analysis. As sensitive material, benzoic acid was added to the standar Fricke gel solution, increasing detector radiosensitivity. Finite element method (FEM) and an inverse problem approach were used to developed an algorithm capable of estimating the diffusion coefficient. The obtained average diffusion coefficient was (1.41±0.03) mm²/h. Also, the proposed mathematical model was capable of comparing experimental measurements with numerical solutions.