Structural and morphological characterization of molybdenum coatings for high gradient accelerating structures

A series of Mo coatings grown on Al2O3 and Cu were prepared via sputtering method. XAS experiments were performed at the Mo K edge to characterize the coating structure and the chemical status of Mo atoms. From the XANES analysis we recognized that all Mo coatings on Al2O3 have a slightly disordered structure with a negligible Mo oxide contribution. Moreover, the chemical state is that of the Mo metal with a negligible oxygen contribution. Compared with Cu based materials, molybdenum is an attractive material for accelerator components and a reliable option for RF linear accelerating structures to achieve high accelerating gradients and low breakdown rates, two fundamental parameters for the next generation of linear accelerators.