Investigation of nanoscale structures by small-angle X-ray scattering in a radiochromic dosimeter

This study examines the nanoscale structures in a radiochromic dosimeter that was based on leucomalachite-green dye and the surfactant sodium dodecyl sulfate (SDS) suspended in a gelatin matrix. Small-angle X-ray scattering was used to investigate the structures of a range of compositions of the dosimeter. When omitting gelatin, ellipsoidal micelles of SDS were formed with a core radius near 15 A, an eccentricity of 1.6, and a head-group shell thickness near 7 angstrom. Gelatin significantly changed the micelles to a cylindrical shape with around three times lower core radius and four times larger shell thickness, which shows that the gelatin is present in the shell and the outer part of the core. Insight into the detailed structure might help to improve the dosimeter performance and increase the dose response to clinically relevant dose levels.