• J. Guo, D.W. Martin, S.G. Tantawi, C. Yoneda
  SLAC, Menlo Park, California

Superconducting RF is increasingly important for particle accelerators. A lot of effort has been made in the SRF material research recently, aiming to find the superconducting materials with better performance. We developed a testing system using a resonant cavity with high quality factor and an interchangeable wall for the testing of different materials. The system is capable for high power RF cryogenic test to find the critical magnetic field at different temperature. The facility can be also used on testing the low temperature properties of the normal conducting material. Different Cu, Nb and MgB2 samples have been tested. In this paper, we will present the most recent development of the system, along with a discussion on the recent testing results.

• J.W. Wang, J.R. Lewandowski, J.W. Van Pelt, C. Yoneda
  SLAC, Menlo Park, California
• B.A. Gudkov, G. Riddone
  CERN, Geneva
• T. Higo, T. Takatomi
  KEK, Ibaraki

A CERN-SLAC-KEK collaboration on high gradient X-band structure research has been established in order to demonstrate the feasibility of the CLIC baseline design for the main linac stably operating at more than 100 MV/m loaded accelerating gradient. Several prototype CLIC structures were successfully fabricated and high power tested. They operated at 105 MV/m with a breakdown rate that meets the CLIC linear collider specifications of < 5·10^-7/pulse/m. This paper summarizes the fabrication technologies including the mechanical design, precision machining, chemical cleaning, diffusion bonding as well as vacuum baking and all related assembly technologies. Also, the tolerances control, tuning and RF characterization will be discussed.