The Coaxial Blade Tuner - Final Report and Evaluation of Operation

The future high gradient superconducting LINACS ask for the use of a compact and cost effective tuner design with no interference with the cavity end group area. The integration of the piezo-assisted fast tuning option made the Coaxial Blade-Tuner, an evolution of the device successfully tested at DESY on the superstructures, the most viable candidate to be included into the future LINACS BCD. The new tuner design is simpler and cheaper with respect to the former, still keeping the required mechanical stiffness. Actually, in the perspective of large scale production and on the basis of the experience acquired so far, two alternative prototypes have been designed and built. They mainly differ for the materials adopted (titanium or stainless steel) and have been optimized to minimize material and construction cost, while fulfilling the performances required for the high gradient cavity operation up to 35 MV/m or even higher. The piezo blade tuner has been extensively and successfully tested both at room temperature and at cold once assembled on a TESLA type cavity in its final configuration. This report contains the full description of the device, starting from the mechanical features till the qualification test results inside the horizontal cryomodule facilities at DESY and at BESSY, showing the fulfillment of all the design requirements.