First Performance Results for the ATLAS Intensity Upgrade Cryomodule
The cryomodule of seven superconducting niobium cavities installed and just commissioned at the middle of the ATLAS linac is the product of four years of effort by the linac development group to incorporate essentially all of the technology and techniques developed here and elsewhere over the past decade. The cavities, optimized for beta=0.077, are the only example of operational low-velocity niobium cavities with performance approaching the fundamental material limits.
The most important contributing factors to this performance, including the design, fabrication, processing and assembly are reviewed, as are a handful of surprises and technical hurdles encountered during final assembly and commissioning. The commissioning, and planned long-term demonstration of this technology in ATLAS, is discussed in the context of future machines and technical developments.