The use of radioactive palladium-103 in brachytherapy has not to be demonstrated. At present, its purification using wet chemical method causes some drawbacks like: production of waste and high cost. A new technique of separation of the radioactive palladium in a solid solution of rhodium by dry method is under investigations. It consists in separating the palladium of the rhodium by annealing the irradiated target. However, this technique induces some difficulties like the diffusion of rhodium in its substrate. The purpose of this master thesis is to find a material able to reduce this interdiffusion. The minimum temperature needed for the separation of the palladium-rhodium couple being higher than 1100°C, this "barrier" material will have to be able to support such temperature.
Different types of materials have been studied: carbon, boron carbide, Sialon, Alon and alumina (Al2O3). All this materials have been investigated in the form of thin films except for boron carbide. A thin film of rhodium is deposited on these layers by DC magnetron sputtering and all this materials have been annealed in vacuum at different temperatures from 800°C to 1100°C. The characterization of the samples has been made by Rutherford Backscattering Spectroscopy (RBS) and added by Resonant Nuclear Reaction Analysis (RNRA) for barriers in carbon. All this analyses were possible thanks to the linear Tandétron accelerator "ALTAÏS" installed in the LARN laboratory.