Manufacturing studies and rf test results of the 1.3 GHz fundamental power coupler prototypes

Abstract

The superconducting radiofrequency electron linear accelerator of the Shanghai HIgh repetition rate XFEL aNd Extreme light facility (SHINE) will use 600 TESLA-style cavities with 1.3 GHz fundamental power couplers for continuous-wave operation. The first batch of 26 1.3 GHz coupler prototypes has been fabricated from three domestic manufacturers for qualification. Several key manufacturing processes have been developed and qualified, including high residual resistivity ratio copper plating, vacuum brazing of ceramic windows, electron beam welding, and titanium nitride coating. In addition, uniform quality control and inspection processes have been established to ensure the power couplers meet the requirements for the intended use in the SHINE project. All the 1.3 GHz coupler prototypes have been power conditioned with 14-kW traveling wave and 7-kW standing wave rf in continuous-wave mode. Even higher power levels have been demonstrated with 20-kW traveling wave and 10-kW standing wave rf, which indicates their robustness.