New 3D radiochromic gel dosimeters with inhibited diffusion

Abstract

Two new radiochromic gels for 3D dosimetry, both with inhibited diffusion, are described. The first dosimeter is based on the radiation-induced creation of a dye Turnbull blue. The dose sensitivity of the gel measured in terms of spectrophotometric absorbance is (5.0 ± 0.1)×10−3 Gy−1cm−1 (1σ) and the background value 24 h after gel preparation is 0.14 cm−1. The diffusion coefficient of the gel stored at 24°C is less than 4x10−3 mm2h−1 (1σ). The second dosimeter makes use of the radiation-induced formation of insoluble mercurous chloride which creates a fog inside an originally bright gel. The dose sensitivity of the dosimeter is (3.8 ± 0.2)x10−2 Gy−1cm−1 (1σ) and its background value 24 h after preparation is 0.18 cm−1. The diffusion coefficient is less than 2x10−4 mm2h−1 (1σ).