New 3D radiochromic gel dosimeters with inhibited diffusion

摘要

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)X10~(-3) Gy~(-1) cm~(-1) (1sigma) and the background value 24 h after gel preparation is 0.14 cm~(-1). The diffusion coefficient of the gel stored at 24 deg C is less than 4X10~(-3) mm~(2) h~(-1) (1sigma). 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~(-1) cm~(-1) (1sigma) and its background value 24 h after preparation is 0.18 cm~(-1). The diffusion coefficient is less than 2X10~(-4) mm~(2) h~(-1) (1sigma).