The DarkSide project - located at the Gran Sasso National Laboratories - aims to directly detect dark matter particles, using a liquid argon detector. One of the key features in the DarkSide-20k experiment is a neutron veto detector, used to reject the background signals caused by neutron interactions. The veto detector will consist of a gadolinium loaded polymethyl methacrylate (PMMA) shell, surrounded by liquid argon. Neutrons capture on the gadolinium which emits multiple gamma rays that interact in liquid argon, producing scintillation light. This light is then detected with dedicated photosensors.
In this context my work is focused on an R&D project to make a uniform gadolinium oxide nano- particle dispersion in a PMMA matrix, starting from the liquid monomer (MMA). Since gadolinium oxide is not mixable in MMA, but the nano grains tend to aggregate and to deposit during the polymerisation - thus causing inhomogeneity in the final product - a functionalization study of the oxide grains with a suitable surfactant is required, in order to create a coating that minimizes the grains clusterisation.