SRF ACTIVITIES AT ACCEL INSTRUMENTS

We report on the current activities and achievements in the field of SRF technology at ACCEL Instruments. During the last two years a wide range of projects covering cavity and component production, cavity surface preparation, SRF module development and construction has been carried out. Details of the results will be presented in the related papers. CAVITY FABRICATION It is widely recognized that TESLA technology is the actual driving motor for the development of high performance superconducting cavities. During the last two years we supplied about 100 TESLA type cavities for laboratories worldwide as supply for XFEL or ILC. The strict application of TESLA quality assurance rules and further improvements developed in house is the basis for high rf performance reached at the different laboratories. The cavity supply is adapted to the specific needs of the customer. It reaches from the bare cavity after final machining to finally tuned cavities with BCP surface preparation and high pressure rinsing. New materials like large grain niobium sheets or even single crystal material demand adaptation of the deep drawing, rolling or electron beam welding processes to changed material parameters. Meanwhile ACCEL supplies TESLA nine cell cavities manufactured from large grain sheet material and single crystal one cell cavities. Together with DESY we developed a process for joining single crystal cavity half cells maintaining the crystal orientation of the base material across the welding joint (1).