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Lange, R.

Paper Title Page
MOPP120 Full Characterization of the Piezo Blade Tuner for Superconducting RF Cavities 838
 
  • A. Bosotti, C. Pagani, N. Panzeri, R. Paparella
    INFN/LASA, Segrate (MI)
  • C. Albrecht, K. Jensch, R. Lange, L. Lilje
    DESY, Hamburg
  • J. Knobloch, O. Kugeler, A. Neumann
    BESSY GmbH, Berlin
 
  Cavity tuners are mechanical devices designed to precisely match the resonant frequency of the superconducting (SC) cavity to the RF frequency synchronous with the beam. The blade tuner is mounted coaxially to the cavity and changes the resonator frequency by varying its length. A high tuning range is desired together with small mechanical hysteresis, to allow easy and reproducible resonator setup operations. High stiffness is also demanded to the tuner system both to ensure mechanical stability and to mitigate the frequency instabilities induced by perturbations. In high gradient SC resonators, the main sources of resonant frequency instability are the Lorentz Force Detuning (LFD) under pulsed mode operation, and the microphonic noise, in continuous wave (CW) with high loaded quality factors. Piezoceramic elements add dynamic tuning capabilities to the system, allowing fast compensation of these instabilities with the help of feed-forward and feedback loops. The piezo blade tuner has been extensively tested both at room temperature and at cold once assembled on a TESLA type cavity in its final configuration. This paper presents the summary of the complete characterization tests.  
WEPD038 Thermal and Structural Modeling of the TTF Cryomodule Cooldown and Comparison with Experimental Data 2494
 
  • S. Barbanotti, P. Pierini
    INFN/LASA, Segrate (MI)
  • K. Jensch, R. Lange, W. Maschmann
    DESY, Hamburg
 
  The study of thermal and structural behavior during cooldown/warmup of long SRF cryostats is important for both the XFEL and ILC, which base the design on the successful TTF design. We present the finite elements analysis of the main internal components of the cryomodules during the transient cooldown and warmup, comparing the data obtained with data taken at DESY on the linac.