The effect of THPS concentration on nPAG microstructure

The microstructures formed within a normoxic polyacrylamide gel (nPAG) dosimeter and their correlation to amount of dose received is investigated through the use of two scanning electron microscope modalities. The effect of gold sputtering onto the samples was examined to determine if it impacted the detectable structures. The evolution of polymer structure with increasing dose is shown to progress from long shard like polymer chains to smooth polymer structures coating the gel surface. It is demonstrated that without gold coating the samples, which is a necessity in high vacuum scanning electron microscopy, that an environmental scanning electron microscope can be used for analysis of polymerized structures. The addition of THPS as an antioxidant is shown to not alter the formation of polymer microstructures when compared to other studies involving THPC. It is also proposed that knowledge of these features could be used to manipulate the deformability, stability and polymerized opacity of an nPAG dosimeter.