Construction of an innovative cylindrical magnetron sputtering source for Isolde Superconductive Nb/Cu QWRs-Master Thesis DANIEL ADRIEN FRANCO LESPINASSE

Author: DANIEL ADRIEN FRANCO LESPINASSE ; Type of thesis: Master Thesis
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In this research, an innovative source was built and were performed the preliminary tests to study a magnetron sputtering configuration in order to deposit quarter wave resonator cavities (QWRs) .This project is based on the deposition of niobium onto copper cavities that will be used for the development of an ion accelerator. To do this, it was required the development of the vacuum chamber using a rotating magnetron , a test cavity and a test cathode, both of them made with stainless steel. The methodology was established depositing stainless steel onto quartz substrates placed along the cavity in order to observe the uniformity of the coating. The results are focused on thickness measurements. In addition to the sample thickness measurements was realized the film stripping test in order to see differences in deposition rates, all over the resonator wall. Were studied three groups of test changing the configuration of the magnetic field and other parameters like sputtering pressure, power and also time of deposition. Finally was found that the vacuum system was successfully assembled and is available for thin film deposition. Preliminary deposition tests with SS were performed and different thicknesses were observed along the cavity. Thickness values are higher on the internal region of the cavity where the target is closer and lower thicknesses are in the top where might be holes in the magnetic field. Also, the appropriate pressure found to reduce differences in thickness along the cavity was 8×10-3 mbar and the stripping test shows that the deposition rates are different on the top of the cavity probably due to the absence of magnetic field. Nowadays, we are modifying the configuration of the magnetron in order to improve the plasma on the top of the cavity.