Characterisation of TruView: a new 3-D reusable radiochromic MethylThymolBlue based gel dosimeter for ionising radiations

摘要

TruView is a new water-equivalent reusable Fricke gel dosimeter based on MethylThymolBlue reactive dye. Details of the characterisation of the TruView MTB gel dosimeter by spectrophotometric measurements and of its reading with the Optical-CT Scanner Vista are described. In this study, the different parameters influencing TruView dose response have been studied and its performances have been compared to chamber and diodes measurements. This gel presents a linear response with dose up to 20 Gy, independent in the investigated range of photon beam energy and dose rate and also a good intra-batch uniformity. Ions diffusion into the matrix homogenizes the gel after a week, losing dosimetric information but allowing a new irradiation to be performed. However, auto-oxidation happens before and after irradiation, degrading the dosimeter response and stability. Storage and reading conditions affect the response as well.