| Paper | Title | Page |
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| THP014 | Recent Results of 1.3 GHz Nine-Cell Superconducting Cavities for the European XFEL | 806 |
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In preparation for the series production of roughly 800 superconducting accelerating structures, several tests with an industrial-like production sequence have been tested for their accelerating gradient and quality factor. The main part of the surface preparation is being done with electropolishing. with ethanol rinse. For the two different final preparation steps namely electropolishing and etching the performance is compared. The results will be also put into the perspective of earlier cavity production cycles that were tested at DESY. |
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| THP018 | Successful Qualification of the Coaxial Blade Tuner | 818 |
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Cavity tuners are needed to precisely tune the narrow-band resonant frequency of superconducting cavities. The Blade Tuner presented is installed coaxially to the cavity and changes the resonator frequency by varying its length. Piezoceramic actuators add dynamic tuning capabilities, allowing fast compensation of main dynamic instabilities as Lorentz Forces, under pulsed operations, and microphonic noise. A prototype piezo Blade Tuner has been assembled on a TESLA cavity and extensively cold tested inside the horizontal cryostats CHECHIA (DESY) and HoBiCaT (BESSY). Then, as suggested by results, a few minor modifications have been implemented thus achieving the current Blade Tuner design. The introduction of thicker blades re-distributed along the circumference allows to increase its stiffness and fulfill European and American pressure vessel codes, while ensuring requested performances and cost. The paper will present the successful characterization tests performed on the prototype, the extensive mechanical analyses made to validate the final model and the results from qualification tests of first revised Blade Tuner produced, to be installed in the second module of ILCTA at FNAL. |