Workshop on High-Power Couplers for Superconducting Accelerators Jefferson Lab
- N. Hilleret
- Newport News, Virginia,USA
A particular interest is accorded, in LAL-Orsay, to the R&D and technology studies on RF power couplers for superconductive cavities. One of the most critical components of those devices is the ceramic RF window that allows the power flux to be injected in the coaxial line. The presence of dielectric window on a high power RF line has a strong influence on the multipactor phenomena. The most important method to reduce the multipactor is to decrease the secondary emission yield of the ceramic window. Due to its low Secondary electron Emission Yield (SEY), TiN thin film is used as a multipactor suppressor coating on RF ceramic coupler windows. In this frame work, TiN deposition was made by magnetron reactive sputtering. XPS and XRD analysis were performed to control the compositions and the stoechiometries of the obtained films. Coating thickness was optimized so that the TiN coating effectively reduces the SEY but does not cause excessive heating, due to ohmic loss. For this purpose, SEY measurements on covered and uncovered TiN Alumina substrates and multipactor level breakdown on TiN coated Copper substrates were performed for different deposit thicknesses.