Secondary electron yield of a thin film coating on the APS rf cavity tuners

A thin film coating of titanium nitride was applied to the surface of rf cavity tuners to reduce secondary electron generated when the existing copper base material is in place. The tuners are used in high-field gradients, where electron heating of the tuner is a problem. By reducing the generation of electrons the temperature of the tuners will be reduced, for better reliability. This paper compares characteristics useful for rf cavity tuners, such as surface composition and secondary electron yield, for copper, titanium-coated copper, and titanium-nitride-coated copper. The process and the setup of equipment used to apply the coatings are summarized